Position measurement method, position control method, measurement method, loading method, exposure method and exposure apparatus, and device manufacturing method

ABSTRACT

An exposure method and apparatus exposes a substrate that is loaded on a stage via a carrier system, with an exposure beam via a projection optical system and a liquid. An object carried by the carrier system is mounted in a depressed section of the stage. Information on a positional relation between the object mounted in the depressed section and the depressed section is obtained. The substrate is loaded on the stage based on the obtained information so that the substrate carried to above the stage by the carrier system is mounted in the depressed section. A part of the substrate mounted in the depressed section is irradiated with the exposure beam via the projection optical system and a liquid immersion area formed by the liquid under the projection optical system.

This is a Divisional of U.S. patent application Ser. No. 13/965,544filed Aug. 13, 2013, which in turn is a Divisional of U.S. patentapplication Ser. No. 12/701,014 filed Feb. 5, 2010 (now U.S. Pat. No.8,576,379), which is a Continuation of U.S. patent application Ser. No.11/730,915, filed Apr. 4, 2007 (now abandoned), which is a Divisional ofU.S. patent application Ser. No. 11/281,544, filed Nov. 18, 2005 (nowU.S. Pat. No. 8,059,260). The disclosure of the prior applications ishereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to position measurement methods, positioncontrol methods, measurement methods, loading methods, exposure methodsand exposure apparatus, and device manufacturing methods, and moreparticularly to a position measurement method in which positioninformation of a plate mounted freely detachable on a moving body ismeasured, a position control method that uses the position measurementmethod, a measurement method in which information related to a platewhere an opening is formed in order to mount an object is measured, aloading method that uses the measurement method, an exposure method thatutilizes the loading method and an exposure apparatus suitable forperforming each of the methods described above, and a devicemanufacturing method that uses the exposure apparatus or the exposuremethod.

2. Description of the Related Art

Conventionally, in a lithography process for manufacturing electronicdevices such as a semiconductor device (an integrated circuit or thelike), a liquid crystal display device, or the like, a reductionprojection exposure apparatus (the so-called stepper) by thestep-and-repeat method that transfers a pattern formed on a mask or areticle (hereinafter generally referred to as a ‘reticle’) onto aphotosensitive object such as a wafer or a glass plate (hereinaftergenerally referred to as a ‘wafer’) on which a resist (a photosensitiveagent) is coated, or a projection exposure apparatus (the so-calledscanning stepper) by the step-and-scan method is mainly used.

Due to higher integration and finer circuit patterns of thesemiconductor devices, in order to improve the resolution of theprojection optical system equipped in the projection exposure apparatus,the wavelength of the exposure light (exposure wavelength) is becomingshorter while the numerical aperture (NA) of the projection opticalsystem is gradually increasing. Meanwhile, depth of focus is becomingsmaller, due to such shorter exposure wavelength and increasingnumerical aperture (larger NA). The exposure wavelength is presumed tobe shorter in the future, and if such a situation continues, the depthof focus may become so small that margin shortage may occur during theexposure operation.

Therefore, as a method of substantially shortening the exposurewavelength while increasing (widening) the depth of focus when comparedwith the depth of focus in the air, the exposure apparatus that utilizesthe immersion exposure method is beginning to gather attention. As theexposure apparatus that utilizes the immersion method, an exposureapparatus that performs exposure in a state where the space between thelower surface of the projection optical system and the wafer surface islocally filled with liquid such as water or an organic solvent is known(refer to, for example, the pamphlet of International Publication No.WO99/49504). In the exposure apparatus according to the pamphlet, theresolution is improved utilizing the fact that the wavelength of theexposure light in the liquid becomes 1/n of the wavelength in the air (nis the refractive index of the liquid which is normally around 1.2 to1.6), and also the depth of focus is substantially increased n timeswhen compared with the case where the same resolution is obtained by aprojection optical system (supposing that such a projection opticalsystem can be made) that does not employ the immersion method. That is,the depth of focus can be substantially increased n times than in theair.

Recently, in wafer stages of the exposure apparatus, a proposal has beenmade of disposing a freely detachable plate that forms a flat sectionsubstantially flush with the wafer in the periphery of the wafer held bythe wafer stage. In the case of using such a detachable plate in thewafer stage, the position of the plate has to be precisely known.

In addition, in the case of using such plate in the wafer stage, anopening (such as an opening with a circular shape in the case of asemiconductor wafer) for positioning the wafer has to be formed in thecenter of the plate. However, for example, in the case the degree ofroundness of the circular opening of the plate is low and the circularshape is deformed or in an ellipse, the gap between the circumferentialsurface of the wafer and the inner circumference surface of the openingbecomes uneven, and inconveniences could occur, such as the wafer cominginto contact with the inner wall surface of the opening of the plate, ornot being able to insert the wafer into the opening of the plate.

In addition, because the gap between the inner wall surface of theopening of the plate and the wafer is extremely small, smooth loadingoperation of the wafer will be difficult if the relative position of thewafer and the plate is not accurately aligned when loading the wafer.

In addition, in the case of the exposure apparatus that utilizes theimmersion method, there was the risk of the liquid flowing into partswhere the gap between the inner circumference edge of the opening of theplate and the outer circumferential edge of the wafer is large.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda first position measurement method in which position information of aplate of a predetermined shape detachably mounted on a moving body ismeasured, the position measurement method comprising: an outer peripheryedge position obtaining process where a part of the plate is detectedwhile a position of the moving body is measured by a measurement unitthat sets a movement coordinate system of the movement body, andposition information of an outer periphery edge of the plate is alsoobtained, based on detection results of the plate and measurementresults of the measurement unit corresponding to the detection results.

According to this method, a part of the plate is detected while theposition of the moving body on which the plate with a predeterminedshape is detachably mounted is measured by the measurement unit thatsets the movement coordinate system of the movement body, and based onthe detection results and the measurement results of the measurementunit corresponding to the detection results, the position information ofthe outer periphery edge of the plate is obtained. Therefore, theposition of the outer periphery edge of the plate can be controlled onthe movement coordinate system set by the measurement unit.

According to a second aspect of the present invention, there is provideda position control method in which the position of a moving body where aplate is detachably mounted is controlled, wherein the position of themoving body is controlled, based on position information of the outerperiphery edge of the plate measured using the position measurementmethod according to the present invention.

According to this method, because the position of the moving body iscontrolled based on the position information of the outer periphery edgeof the plate measured using the position measurement method according tothe present invention, the position of the object can be controlledtaking into consideration the position of the outer periphery edge ofthe plate.

The position control method of the present invention can be used, forexample, to control the position of a moving body on which an objectsubject to exposure is placed in an exposure apparatus. Accordingly, itcan also be said from a third aspect that the present invention is afirst exposure apparatus that uses the position control method of thepresent invention.

According to a fourth aspect of the present invention, there is provideda measurement method in which information on a plate where an opening isformed to place an object, the plate being detachably mounted on amoving body, is measured, the measurement method comprising: an innerperiphery edge position obtaining process where a part of the plate isdetected and position information of an inner periphery edge of theopening is obtained, based on detection results of the plate.

According to this method, a part of the plate where the opening isformed to place the object is detected, the plate being detachablymounted on the moving body, and based on the detection results theposition information of the inner periphery edge of the opening isobtained. Therefore, based on the position information on the innerperiphery edge, it becomes possible to calculate the position and theshape of the opening.

According to a fifth aspect of the present invention, there is provideda first loading method in which an object is loaded on a moving bodywhere a plate that has an opening to place an object is detachablymounted, wherein the object is loaded into the opening of the plate onthe moving body, based on position information of the inner peripheryedge of the opening of the plate obtained using the measurement methodaccording to the present invention.

According to this method, the object is loaded into the opening of theplate on the moving body, based on the position information of the innerperiphery edge of the opening of the plate obtained using themeasurement method of the present invention. Accordingly, it becomeseasy to load the object to the opening of the plate on the moving body.

According to a sixth aspect of the present invention, there is provideda first exposure method in which an object is exposed, the exposuremethod comprising: a loading process in which the object is loaded intoan opening in the plate on a moving body using the loading methodaccording to the present invention; and an irradiation process in whichan exposure beam is irradiated on the object loaded on the moving body.

According to this method, the object is loaded into the opening of theplate on the moving body using the first loading method of the presentinvention, and exposure is performed irradiating the exposure beam onthe object loaded on the moving body.

According to a seventh aspect of the present invention, there isprovided a second loading method in which an object subject toprocessing is loaded into a depressed section on an upper end section ofa moving body, the loading method comprising: a placing process in whichan object is placed in the depressed section on the moving body; and anobtaining process in which information on a position relation between aninner periphery edge of the depressed section and the object placedwithin the depressed section is obtained.

In this case, ‘object’ is a concept that includes the object subject toprocessing. More specifically, in the placing process, an object subjectto processing may be placed within the depressed section on the movingbody, or other objects, such as an object used only for the purpose ofobtaining the position relation described above may be placed.

In any case, in the obtaining process, the information on the positionrelation between the inner periphery edge of the depressed section andthe object placed within the depressed section is obtained. Accordingly,based on the position relation that has been obtained, it becomespossible to load the object in the depressed section of the moving bodyat a predetermined positional relation.

According to an eighth aspect of the present invention, there isprovided a second exposure method in which an object subject toprocessing is exposed, the exposure method comprising: a placing processin which the object subject to processing is placed within a depressedsection of a moving body using the second loading method according tothe present invention; and an irradiation process in which an exposurebeam is irradiated on the object subject to processing placed within thedepressed section of the moving body.

According to this method, the object subject to processing is placedinto the depressed section on the moving body using the second loadingmethod of the present invention, and exposure is performed irradiatingthe exposure beam on the object subject to exposure placed in thedepressed section of the moving body.

According to a ninth aspect of the present invention, there is provideda second exposure apparatus that irradiates an exposure beam on anobject, the exposure apparatus comprising: a first stage on which aplate of a predetermined shape is detachably mounted a positionmeasurement system that measures a position of the first stage; adetection unit that can detect a part of the first stage; and an outerperiphery edge position obtaining unit that detects a part of the plateusing the detection unit while measuring a position of the first stageusing the position measurement system, and based on detection results ofthe plate and measurement results of the position measurement systemcorresponding to the detection results, obtains position information ofan outer periphery edge of the plate.

According to this apparatus, the outer periphery edge position obtainingunit detects a part of the plate using the detection unit, whilemeasuring the position of the first stage on which the plate having apredetermined shape is detachably mounted using the position measurementsystem, and also obtains the position information of the outer peripheryedge of the plate based on the detection results and the measurementresults of the position measurement system corresponding to thedetection results. Therefore, it becomes possible to control theposition of the outer periphery edge of the plate mounted on the firststage on a movement coordinate system set by the position measurementsystem.

According to a tenth aspect of the present invention, there is provideda third exposure apparatus that irradiates an exposure beam on anobject, the exposure apparatus comprising: an exposure stage on which aplate of a predetermined shape having an opening formed where the objectis placed is mounted; a position measurement system that measures aposition of the exposure stage; a detection unit that can detect a partof the exposure stage; and an inner periphery edge position obtainingunit that detects a part of the plate using the detection unit whilemeasuring a position of the exposure stage using the positionmeasurement system, and based on detection results of the plate andmeasurement results of the position measurement system corresponding tothe detection results, obtains position information of an innerperiphery edge of the opening.

According to this apparatus, the inner periphery edge position obtainingunit detects a part of the plate using the detection unit, whilemeasuring the position of the exposure stage using the positionmeasurement system, and also obtains the position information of theinner periphery edge of the opening based on the detection results andthe measurement results of the position measurement system correspondingto the detection results. Therefore, it becomes possible to obtain theinformation of the position and shape of the opening, based on theposition information of the inner periphery edge.

In the lithography process, by using the first to third exposureapparatus of the present invention, a pattern can be formed on an objectwith good precision, which allows microdevices to be manufactured withgood yield. Similarly, in the lithography process, by using the firstand second exposure methods of the present invention, a pattern can beformed on an object with good precision, which allows microdevices to bemanufactured with good yield. Accordingly, further from another aspect,the present invention can also be said to be a device manufacturingmethod that uses one of the first to third exposure apparatus of thepresent invention, or either the first or second exposure method of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings;

FIG. 1 is a view that shows a schematic configuration of an exposureapparatus in an embodiment;

FIG. 2 is a perspective view that shows a stage unit in FIG. 1;

FIG. 3 is a perspective view that shows a measurement stage in FIG. 1;

FIG. 4 is a planar view that shows a wafer table;

FIG. 5 is a view for describing an arrangement of an interferometersystem;

FIG. 6 is a block diagram that shows a main arrangement of a controlsystem of an exposure apparatus in an embodiment;

FIG. 7 is a flow chart that shows a processing algorithm of (a CPUinside) a main controller when a wafer table performs a recoveryoperation to a reference state;

FIG. 8 is a view for describing conditions to start the processingalgorithm shown in FIG. 7 that shows an example of a position of a wafertable WTB upon the start;

FIG. 9A is a view that shows a state where the position of the firstmeasurement point is set in an imaging field of an alignment system whenposition information of the outer periphery edge of a liquid-repellentplate is obtained;

FIG. 9B is a view that shows a state where the position of the secondmeasurement point is set in the imaging field of the alignment systemwhen position information of the outer periphery edge of theliquid-repellent plate is obtained;

FIG. 9C is a view that shows a state where the position of the thirdmeasurement point is set in the imaging field of the alignment systemwhen position information of the outer periphery edge of theliquid-repellent plate is obtained;

FIG. 9D is a view that shows a state where the position of the fourthmeasurement point is set in the imaging field of the alignment systemwhen position information of the outer periphery edge of theliquid-repellent plate is obtained;

FIG. 10A is a view that shows a state of a movement of wafer table WTBwhen position information of a plurality of measurement points on anedge of the liquid-repellent plate on the +Y end side is sequentiallymeasured;

FIG. 10B is a view that shows a state in the case three measurementpoints are set on each of the four edges of the liquid-repellent plate;

FIG. 11 is a flowchart (No. 1) that shows a processing algorithm of (aCPU inside) a main controller when a series of processing is performedduring a period from a liquid-repellent plate exchange on a wafer tableuntil the next liquid-repellent plate exchange;

FIG. 12 is a flowchart (No. 2) that shows a processing algorithm of (aCPU inside) a main controller when a series of processing is performedduring a period from a liquid-repellent plate exchange on a wafer tableuntil the next liquid-repellent plate exchange;

FIG. 13 is a flowchart that shows a subroutine of step 222;

FIG. 14 is a flowchart that shows a subroutine of step 236;

FIG. 15A is a view that shows a state where the position of the firstmeasurement point is set in an imaging field of an alignment system whenposition information of the inner periphery edge of an opening of aliquid-repellent plate is obtained;

FIG. 15B is a view that shows a state where the position of the secondmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 15C is a view that shows a state where the position of the thirdmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 15D is a view that shows a state where the position of the fourthmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 16A is a view that shows a state where the position of the fifthmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 16B is a view that shows a state where the position of the sixthmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 16C is a view that shows a state where the position of the seventhmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 16D is a view that shows a state where the position of the eighthmeasurement point is set in the imaging field of the alignment systemwhen position information of the inner periphery edge of the opening ofthe liquid-repellent plate is obtained;

FIG. 17A is a schematic view that models a state where imaging data ofeight points on an inner periphery edge of an opening of aliquid-repellent plate is obtained;

FIG. 17B is a schematic view that models a state where imaging data ofeight points on an outer periphery edge of a tool wafer is obtained;

FIG. 18 is an enlarged side view of a vicinity of an outer peripheryedge section of a liquid-repellent plate;

FIG. 19A is a view (No. 1) for describing a modified example;

FIG. 19B is a view (No. 2) for describing a modified example;

FIG. 19C is a view (No. 3) for describing a modified example;

FIG. 19D is a view (No. 4) for describing a modified example;

FIG. 20A is a view (No. 5) for describing a modified example;

FIG. 20B is a view (No. 6) for describing a modified example; and

FIG. 20C is a view (No. 7) for describing a modified example.

DESCRIPTION OF THE EMBODIMENT

An embodiment of the present invention is described below, referring toFIGS. 1 to 17B.

FIG. 1 shows a schematic configuration of an exposure apparatus 100 inan embodiment that is suitable for performing a position measurementmethod, a position control method, a measurement method, a loadingmethod, and an exposure method related to the present invention.Exposure apparatus 100 is a projection exposure apparatus by thestep-and-scan method, that is, the so-called scanning stepper (alsocalled a scanner). Exposure apparatus 100 is equipped with anillumination system 10, a reticle stage RST that holds reticle R, aprojection unit PU, a stage unit 150 that has a wafer stage WST and ameasurement stage MST, a control system for these parts, and the like.On wafer stage WST, a wafer W is to be mounted.

As is disclosed in, for example, Kokai (Japanese Unexamined PatentApplication Publication) No. 2001-313250 and its corresponding U.S.Patent Application Publication No. 2003/0025890 description or the like,illumination system 10 includes an illuminance uniformity opticalsystem, which includes parts such as a light source and an opticalintegrator (a fly-eye lens, an internal reflection type integrator, adiffractive optical element, and the like). Illumination system 10 alsoincludes a beam splitter, a relay lens, a variable ND filter, a reticleblind, and the like (all of which are not shown). As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the above disclosures ofthe publication and the U.S. Patent application publication descriptionare incorporated herein by reference.

In illumination system 10, a slit-shaped illumination area set by thereticle blind on reticle R is illuminated with a substantially uniformilluminance by an illumination light (exposure light) IL. In this case,for example, an ArF excimer laser beam (wavelength: 193 nm) is used asillumination light IL.

On reticle stage RST, reticle R on which a circuit pattern or the likeis formed on its pattern surface (the lower surface in FIG. 1) is fixed,for example, by vacuum suction or the like. Reticle stage RST is drivenby a reticle stage drive system 11 (not shown in FIG. 1, refer to FIG.6), which includes parts such as linear motors, and the stage can befinely driven within an XY plane perpendicular to the optical axis ofillumination system 10 (coincides with an optical axis AX of aprojection optical system PL that will be described later). Reticlestage RST is also drivable at a designated scanning speed in apredetermined scanning direction (in this case, a Y-axis direction,which is the lateral direction of the page surface in FIG. 1).

The position (including rotation around a Z-axis) of reticle stage RSTwithin a stage movement plane is constantly detected at a resolution of,e.g., around 0.5 to 1 nm, by a reticle laser interferometer (hereinafterreferred to as a ‘reticle interferometer’) 116, via a movable mirror 15(in actual, a Y movable mirror that has a reflection surface orthogonalto the Y-axis direction and an X movable mirror that has a reflectionsurface orthogonal to an X-axis direction are arranged). The measurementvalues of reticle interferometer 116 are sent to a main controller 20(not shown in FIG. 1, refer to FIG. 6), and based on the measurementvalues, main controller 20 calculates the position of reticle stage RSTin the X-axis direction, the Y-axis direction, and a θz direction(rotation direction around the Z-axis), as well as control the position(and speed) of reticle stage RST by controlling reticle stage drivesystem 11, based on the calculation results. Instead of movable mirror15, the end surface of reticle stage RST may be mirror polished so as toform a reflection surface (corresponding to the reflection surface ofmovable mirror 15).

Above reticle R, a pair of reticle alignment detection systems RAa andRAb, each constituted by a TTR (Through The Reticle) alignment opticalsystem, is arranged in the X-axis direction at a predetermined distance.With this system, the light of the exposure wavelength is used toobserve a pair of reticle alignment marks on reticle R and a pair offiducial marks on measurement stage MST corresponding to the reticlealignment marks (hereinafter referred to as ‘a first fiducial mark’) atthe same time, via projection optical system PL. As reticle alignmentdetection systems RAa and RAb, systems having a structure similar to theones disclosed in, for example, Kokai (Japanese Unexamined PatentApplication Publication) No. 7-176468 and the corresponding U.S. Pat.No. 5,646,413, are used. As long as the national laws in designatedstates (or elected states), to which this international application isapplied, permit, the above disclosures of the publication and the U.S.Patent are incorporated herein by reference.

Projection unit PU is arranged below reticle stage RST in FIG. 1.Projection unit PU includes a barrel 40 and projection optical systemPL, which consists of a plurality of optical elements held in apredetermined positional relation within barrel 40. As projectionoptical system PL, a dioptric system is used, consisting of a pluralityof lenses (lens elements) that share an optical axis AX in the Z-axisdirection. Projection optical system PL is, for example, a both-sidetelecentric dioptric system that has a predetermined projectionmagnification (such as one-quarter or one-fifth times) is used.Therefore, when illumination light IL from illumination system 10illuminates the illumination area on reticle R, illumination light ILthat has passed through reticle R forms a reduced image of the circuitpattern within the illumination area on reticle R (a partial reducedimage of the circuit pattern) on wafer W whose surface is coated with aresist (photosensitive agent), on an area (exposure area) conjugate withthe illumination area, via projection unit PU (projection optical systemPL).

In exposure apparatus 100 of the embodiment, because exposure isperformed by applying the immersion method, the opening on the reticleside becomes larger with the substantial increase of the numericalaperture NA. Therefore, in a dioptric system consisting only of lenses,it becomes difficult to satisfy the Petzval condition, which tends tolead to an increase in the size of the projection optical system. Inorder to prevent such an increase in the size of the projection opticalsystem, a catadioptric system that includes mirrors and lenses may alsobe used.

In addition, in exposure apparatus 100 of the embodiment, becauseexposure is performed by applying the immersion method, in the vicinityof a lens 91 (hereinafter also referred to as a ‘tip lens’) thatconstitutes a part of projection optical system PL located closest tothe image plane (close to wafer W), a liquid supply nozzle 51A and aliquid recovery nozzle 51B that constitute a part of an immersionmechanism 132 is arranged.

To liquid supply nozzle 51A, a supply pipe (not shown) that has one endconnecting to a liquid supply unit 88 (not shown in FIG. 1, refer toFIG. 6) is connected, whereas to liquid recovery nozzle 51B, a recoverypipe (not shown) that has one end connecting to a liquid recovery unit92 (not shown in FIG. 1, refer to FIG. 6) is connected.

Liquid supply unit 88 includes a tank for the liquid, a compressionpump, a temperature control unit, valves for controlling thesupply/suspension of the liquid to the supply pipes, and the like. Asthe valves, for example, it is desirable to use flow control valves sothat not only the supply/suspension of the liquid but also the flow rateof the liquid can be adjusted. The temperature control unit adjusts thetemperature of the liquid in the liquid tank so that the temperature ofthe liquid is substantially around the same level as the temperaturewithin the chamber (not shown) where the exposure apparatus main body ishoused.

Exposure apparatus 100 does not have to fully equip the tank for theliquid, the compression pump, the temperature control unit, the valves,and the like, and at least a part of such components can be substitutedby the equipment in the factory where exposure apparatus 100 isinstalled.

Liquid recovery unit 92 includes a tank for the liquid and a suctionpump, and valves for controlling the recovery/suspension of the liquidvia the recovery pipes, and the like. As the valves, it is desirable touse flow control valves, corresponding to the valves on the liquidsupply unit 88 side.

Exposure apparatus 100 does not have to fully equip the tank for theliquid, the suction pump, the valves, and the like, and at least a partof such components can be substituted by the equipment in the factorywhere exposure apparatus 100 is installed.

As the liquid above, in this case, pure water (hereinafter, simplyreferred to as ‘water’ except for cases when further reference isnecessary) that transmits the ArF excimer laser beam (light having thewavelength of 193 nm) will be used. Pure water can be obtained easily bylarge quantity in a semiconductor manufacturing site or the like, and isalso good for the photoresist on the wafer and the optical lensesbecause there are no adverse effects.

Refractive index n of the water to the ArF excimer laser beam isapproximately 1.44. In such water, the wavelength of illumination lightIL is shortened to 193 nm×1/n=around 134 nm.

Liquid supply unit 88 and liquid recovery unit 92 are each equipped witha controller, and the controllers operate under the control of maincontroller 20 (refer to FIG. 6). In response to the instructions frommain controller 20, the controller of liquid supply unit 88 opens thevalve connecting to the supply pipe to a predetermined degree, and thensupplies the water between tip lens 91 and wafer W (or a plate that willbe described later) via liquid supply nozzle 51A. In addition, at thispoint, the controller of liquid supply unit 92 opens the valveconnecting to the recovery pipe to a predetermined degree in response tothe instructions from main controller 20, and then recovers the waterfrom between tip lens 91 and wafer W into liquid recovery unit 92 (theliquid tank) via liquid recovery nozzle 51B. At this point, maincontroller 20 gives instructions to the controller of liquid supply unit88 and the controller of liquid recovery unit 92 so that the amount ofwater supplied between tip lens 91 and wafer W from liquid supply nozzle51A and the amount of water recovered via liquid recovery nozzle 51B isconstantly equal. Accordingly, a constant amount of water Lq (refer toFIG. 1) is held between tip lens 91 and wafer W. In this case, water Lqheld between tip lens 91 and wafer W is constantly circulated.

As is obvious from the description so far, immersion mechanism 132 is alocal immersion mechanism that includes liquid supply unit 88, liquidrecovery unit 92, supply pipes, recovery pipes, liquid supply nozzle51A, liquid recovery nozzle 51B, and the like, and in the case ofexposing wafer W, a liquid immersion area is formed on a part of waferW.

Even in the case measurement stage MST is located below projection unitPU, it is possible to fill in the water between measurement table MTB(to be described later) and tip lens 91 as in the description above.

In the description above, only one liquid supply nozzle and one liquidrecovery nozzle were arranged for the sake of simplicity. However, thearrangement is not limited to this, and for example, an arrangement thathas a plurality of nozzles may be employed, as is disclosed in thepamphlet of International Publication No. WO99/49504. The point is, anyarrangement may be employed as long as the liquid can be suppliedbetween optical member (tip lens) 91 at the tip of projection opticalsystem PL and wafer W. For example, the immersion mechanism disclosed inthe pamphlet of International Publication No. WO2004/053955, or theimmersion mechanism disclosed in the European Patent ApplicationPublication No. 1420298 description may also be applied to the exposureapparatus in this embodiment.

Stage unit 150 is equipped with a frame caster FC, a base platform 12arranged on frame caster FC, wafer stage WST and measurement stage MSTarranged above the upper surface of base platform 12, an interferometersystem 118 (refer to FIG. 6) that includes interferometers 16 and 18 formeasuring the positions of stage WST and stage MST, and a stage drivesystem 124 (refer to FIG. 6) for driving stages WST and MST.

As is obvious from FIG. 2, which is a perspective view of stage unit150, frame caster FC is composed of a roughly plate-shaped member, onwhich protruding sections FCa and FCb whose longitudinal direction is inthe Y-axis direction are integrally formed in the vicinity of the edgesections on both sides in the X-axis direction.

Base platform 12 is composed of a plate-shaped member, which is alsoreferred to as a surface table, and is arranged on an area betweenprotruding sections FCa and FCb of frame caster FC. The degree offlatness of the upper surface of base platform 12 is extremely high, andthe upper surface serves as a guide surface when wafer stage WST andmeasurement stage MST moves.

As is shown in FIG. 2, wafer stage WST is equipped with a wafer stagemain body 28 arranged above base platform 12, and a wafer table WTBmounted on wafer stage main body 28 via a Z-tilt drive mechanism (notshown). In actual, Z-tilt drive mechanism includes three actuators(e.g., voice coil motors) or the like that support wafer table WTB onwafer stage main body 28, and Z-tilt drive mechanism finely drives wafertable WTB in directions of three degrees of freedom, in the Z-axisdirection, a θx direction (rotation direction around the X-axis), and aθy direction (rotation direction around the Y-axis).

Wafer stage main body 28 is composed of a hollow member extending in theX-axis direction that has a rectangular framed sectional shape. On thelower surface of wafer stage main body 28, a plurality of (e.g., four)gas hydrostatic bearings (not shown) such as air bearings is arranged,and wafer stage WST is supported in a non-contact manner via thebearings, via a clearance of around several μm above the guide surfacepreviously described.

As is shown in FIG. 2, above protruding section FCa of frame caster FC,a Y-axis stator 86 is arranged, extending in the Y-axis direction.Similarly, above protruding section FCb of frame caster FC, a Y-axisstator 87 is arranged, extending in the Y-axis direction. Y-axis stators86 and 87 are supported by levitation by the gas hydrostatic bearings(not shown) such as air bearings arranged on the lower surface of thestators, via a predetermined clearance with respect to the upper surfaceof protruding sections FCa and FCb. In the embodiment, Y-axis stators 86and 87 are each configured by a magnetic pole unit that has a pluralityof permanent magnets arranged along the Y-axis direction at apredetermined distance.

Inside wafer stage main body 28, a mover 90 is installed, consisting ofa magnetic pole unit whose cross-sectional shape resembles the letter Uand having a plurality of permanent magnets arranged along the X-axisdirection at a predetermined distance.

In the space inside mover 90, an X-axis stator 80 extending in theX-axis direction is inserted. X-axis stator 80 is configured by anarmature unit that has a plurality of armature coils arranged along theX-axis direction at a predetermined distance. In this case, mover 90consisting of the magnetic pole unit and X-axis stator 80 consisting ofthe armature unit constitute a moving magnet type X-axis linear motorthat drives wafer stage WST in the X-axis direction. Hereinafter, theX-axis linear motor will be appropriately referred to as an X-axislinear motor 80, using the same reference numeral as its stator (thestator for the X-axis), X-axis stator 80. As the X-axis linear motor, amoving coil type linear motor may also be used, instead of the movingmagnet type linear motor.

On both ends of X-axis stator 80 in the longitudinal direction, forexample, movers 82 and 83 consisting of armature units incorporated witha plurality of armature coils arranged along the Y-axis direction at apredetermined distance are respectively fixed. Movers 82 and 83 are eachinserted into Y-axis stators 86 and 87 from the inside. That is, in theembodiment, movers 82 and 83 consisting of the armature units and Y-axisstators 86 and 87 consisting of the magnetic pole units constitute twoY-axis linear motors of a moving coil type. Hereinafter, the two Y-axislinear motors will be appropriately referred to as Y-axis linear motor82 and Y-axis linear motor 83, using the same reference numerals as themovers, Y-axis movers 82 and 83. As the Y-axis linear motors 82 and 83,linear motors of the moving magnet type may also be used.

That is, wafer stage WST is driven in the X-axis direction by X-axisliner motor 80, and is also driven in the Y-axis direction integrallywith X-axis linear motor 80 by the pair of Y-axis linear motors 82 and83. In addition, by slightly changing the drive force in the Y-axisdirection generated by Y-axis linear motors 82 and 83, wafer stage WSTcan also be rotationally driven in the Oz direction.

As is shown in the planar view of FIG. 4, wafer table WTB is virtually asquare shape in a planar view, and on the upper surface, a wafer holderWH by the pin chuck method that holds wafer W and a plate holder PH isarranged.

As is shown in FIG. 4, wafer holder WH is equipped with a plurality offirst pins 32 arranged at a predetermined distance within a circulararea of a predetermined dimension in the center of the upper surface ofwafer table WTB, a first rim section 30 consisting of a ring-shapedprotruding section that surrounds the circular area in which theplurality of first pins are arranged, three cylindrical shaped secondrim sections 35A, 35B, and 35C that are respectively projecting at theapex positions of a virtually equilateral triangle where the distancefrom the center of the circular area (holder center) is the same, andthe like. The tip of each of the first pins 32 and the upper end surfaceof the second rim sections 35A, 35B, and 35C are set at substantiallythe same height.

In each of the inner circumference of the second rim sections 35A, 35B,and 35C, a through hole 39 that has a circular shape in a planar view isformed, and inside through holes 39, vertical movement pins (center ups)34 a, 34 b, and 34 c that have a columnar shape are respectivelyarranged movable in the vertical direction (the Z-axis direction, whichis the direction orthogonal to the page surface of FIG. 4). The threecenter ups 34 a to 34 c can be moved up and down in the verticaldirection (the Z-axis direction, which is the direction orthogonal tothe page surface of FIG. 4) simultaneously by the same amount, via avertical movement mechanism (not shown) that constitutes a part of stagedrive system 124 (refer to FIG. 6). On wafer loading/unloading, bycenter ups 34 a to 34 c being driven by the vertical movement mechanism,wafer W can be supported from below by center ups 34 a to 34 c, or canbe vertically moved in the supported state.

As is shown in FIG. 4, in the circular area surrounded by the first rimsection 30 on the upper surface of wafer table WTB, a plurality ofexhaust ports 36 are formed, arranged radially (in three radial linedirections spaced apart at a center angle of substantially 120°) fromthe center of the circular area (holder center) at a predetermineddistance. Exhaust ports 36 are formed at positions that do not interferewith the first pins 32. Each exhaust port 36 connects to exhaust paths38A, 38B, and 38C, which are formed inside wafer table WTB, via thepiping directly under the ports, and exhaust paths 38A, 38B, and 38Cconnect to a first vacuum exhaust mechanism 44 (refer to FIG. 6), viavacuum exhaust piping 41 a, 41 b, and 41 c, respectively.

In the embodiment, when wafer W is loaded on wafer holder WH on wafertable WTB, main controller 20 begins a vacuum exhaust operation via thefirst vacuum exhaust mechanism 44. And, by this operation, a negativestate is created inside the space surrounded by wafer W, the first rimsection 30, and the three second rim sections 35A, 35B, and 35C, andwafer W is held by suction by the plurality of the first pins 32, thefirst rim section 30, and the three second rim sections 35A, 35B, and35C.

On the upper surface of wafer table WTB on the outer side of the firstrim section 30, a third rim section 45 is formed, consisting of aring-shaped protruding section concentric with the first rim section 30.On the outer side of the third rim section 45, a depressed section 49 isformed whose inner side is divided by the third rim section 45 and theouter side is surrounded by an outer partition wall 48 of wafer tableWTB. On the inner bottom surface of depressed section 49, a plurality ofsecond pins 53 whose tips are substantially the same height as the thirdrim section 45 and outer partition wall 48 is arranged at apredetermined distance. In this case, the height of the upper endsurface of the third rim section 45 and outer partition wall 48 is set alittle lower than the height of the first rim section 30. And, on thethird rim section 45, outer partition wall 48, and the plurality ofsecond pins 53 that are configured as is described above, asubstantially square liquid-repellent plate (e.g., a water-repellentplate) 50 that has a circular opening 50 a in the center is detachablymounted. Liquid-repellent plate 50 is mounted on wafer table WTB in astate where the entire outer periphery of liquid-repellent plate 50projects outward a little than outer partition wall 48. That is, plateholder PH by the pin chuck method that holds liquid-repellent plate 50is configured including the third rim section 45, outer partition wall48, and the plurality of second pins 53 that are arranged on the uppersurface of wafer table WTB.

In the area constituting a part of plate holder PH, divided by the thirdrim section 45 and outer partition wall 48 where the plurality of secondpins 53 are arranged, a plurality of exhaust ports (not shown) arearranged similarly to wafer holder WH described above at a predetermineddistance, and each exhaust port connects to exhaust paths (not shown)formed inside wafer table WTB, via the piping directly under the ports,and these exhaust paths connect to a second vacuum exhaust mechanism 56shown in FIG. 6, via the respective vacuum exhaust piping (not shown).

In the embodiment, main controller 20 vacuum suctions the inside of thespace surrounded by liquid-repellent plate 50, the third rim section 45,and the outer partition wall 48 (the inner space of depressed section49) via the second vacuum exhaust mechanism 56, so that theliquid-repellent plate 50 is held by suction by plate holder PH. Inorder to make liquid-repellent plate 50 easily detachable, for example,vertical movement pins similar to center ups 34 a to 34 c may bearranged within the space above, and main controller 20 may control thedrive mechanism of the vertical movement pins.

In the embodiment, the height of each parts that respectively constitutewafer holder WH and plate holder PH is set so that the upper surface ofliquid-repellent plate 50 held by suction on plate holder PH describedabove and the surface of wafer W held by suction on wafer holder WH aresubstantially flush (refer to FIG. 1). In addition, the innercircumferential edge of opening 50 a of liquid-repellent plate 50substantially coincides with the inner circumference wall of the thirdrim section 45, when liquid-repellent plate 50 is in a state held byplate holder PH. That is, in the embodiment, on the inner side of thethird rim section 45 and the inner wall surface of opening 50 a ofliquid-repellent plate 50, a depressed section 140 where wafer W isloaded is formed, and in depressed section 140, wafer holder WH isarranged. In addition, the shape and size of opening 50 a is set so thatthe clearance between the outer circumferential edge of wafer W and theinner circumferential edge of opening 50 a of liquid-repellent plate 50is a value around 0.1 to 0.4 mm. In addition, in a state where wafer Wis held by wafer holder WH, a surface that appears to be completely flatis formed on the upper surface of wafer table WTB.

Wafer table WTB is made of a material that has a low thermal expansionrate, such as ceramics or the like, which has a certain level ofelasticity, and by etching the surface of a substantially squarematerial such as ceramics, the first rim section 30, the second rimsections 35A, 35B, and 35C, the third rim section 45, the plurality offirst pins 32, and the plurality of second pins 53 are integrallyformed.

On the surface of liquid-repellent plate 50, a liquid-repellenttreatment (in this case, water-repellent treatment such aswater-repellent coating) that uses fluorine-containing material isapplied, and a liquid-repellent surface (a water-repellent surface) isformed. The liquid-repellent (water-repellent) surface ofliquid-repellent plate 50 is generally sensitive to light in the farultraviolet region or the vacuum ultraviolet region, and the irradiationof exposure light (illumination light) IL deteriorates theliquid-repellent (water-repellent) performance. In addition, becausetraces of liquid (such as water marks) may be formed on the uppersurface of liquid-repellent plate 50, liquid-repellent plate 50 is madeeasily detachable (exchangeable). Incidentally, besides than the vacuumsuction method, liquid-repellent plate 50 may also be held by othermethods such as the electrostatic suction method.

In addition, a resist (a photosensitive agent) is coated on the surfaceof wafer W. In the embodiment, as an example, a photosensitive agent forthe ArF excimer laser that has liquid repellency (water repellency,contact angle 80° to 85°) is used as the photosensitive agent. As amatter of course, a material for forming a topcoat layer that has liquidrepellency (contact angle to the liquid, 90° to 120°) may be coated onthis photosensitive agent. Incidentally, the surface of wafer W does notnecessarily have to be liquid-repellent, and a resist whose contactangle to the liquid is around 60° to 80° may also be used. In addition,the liquid-repellent treatment may be applied also to the side surfaceand a part of the back surface of wafer W. Similarly, theliquid-repellent treatment may be applied also to at least a part ofwafer holder WH and plate holder PH.

The position of wafer table WTB configured in the manner described aboveis measured by interferometer system 118 (refer to FIG. 6). Details onthe measurement will be described later in the description.

As is shown in FIG. 2, measurement stage MST is configured combining aplurality of components such as a Y stage 81 whose longitudinaldirection is the X-axis direction. Measurement stage MST is supported ina non-contact manner via a clearance of several μm above the uppersurface (guide surface) of base platform 12 via a plurality of gashydrostatic bearings such as air bearings arranged in the lowest surface(the lower surface of the member closest to base platform 12).

As is obvious from the perspective view in FIG. 3, measurement stage MSTis equipped with a measurement stage main body 81 c that has arectangular plate shape extending narrowly in the X-axis direction, Ystage 81 that has a pair of protruding sections 81 a and 81 brespectively fixed on both ends of the upper surface of measurementstage main body 81 c in the X-axis direction, a leveling table 52arranged above the upper surface of measurement stage main body 81 c,and measurement table MTB installed above leveling table 52.

On the end surface of both one end and the other end of measurementstage main body 81 c, which constitutes a part of Y stage 81, in theX-axis direction, movers 84 and 85 consisting of armature units thatincorporate a plurality of armature coils arranged along the Y-axisdirection at a predetermined distance are respectively fixed. Movers 84and 85 are inserted inside Y-axis stators 86 and 87, respectively. Thatis, in the embodiment, movers 84 and 85 consisting of armature units andY-axis stators 86 and 87 consisting of magnetic pole units in whichmovers 84 and 85 are respectively inserted constitute two moving coiltype Y-axis linear motors. Hereinafter, the two Y-axis linear motorsdescribed above will be appropriately referred to as Y-axis linear motor84 and Y-axis linear motor 85, using the same reference numerals as themovers 84 and 85. In the embodiment, Y-axis linear motors 84 and 85drive the entire measurement stage MST in the Y-axis direction. As theY-axis linear motors 82 and 83, linear motors of the moving magnet typemay also be used.

On the bottom surface of measurement stage main body 81 c, the pluralityof gas hydrostatic bearings is arranged. On the upper surface ofmeasurement stage main body 81 c on both one side and the other side inthe X-axis direction on the edge near the +Y side, the pair ofprotruding sections 81 a and 81 b is fixed facing each other. In betweenprotruding sections 81 a and 81 b, stators 61 and 63 each extending inthe X-axis direction within the XY plane are installed, arranged in theZ-axis direction (vertically) at a predetermined distance.

On the end surface of leveling table 52 on the +X side, a mover of an Xvoice coil motor 54 a is arranged, and the stator of X voice coil motor54 a is fixed to the upper surface of measurement stage main body 81 c.Further, on the end surface of leveling table 52 on the −Y side, moversof Y voice coil motors 54 b and 54 c are respectively arranged, and thestators of Y voice coil motors 54 b and 54 c are fixed to the uppersurface of measurement stage main body 81 c. X voice coil motor 54 a isconfigured of, for example, a mover composed of a magnetic pole unit anda stator composed of an armature unit, and a drive force in the X-axisdirection is generated by an electromagnetic interaction between themover and the stator. In addition, Y voice coil motors 54 b and 54 c arealso similarly configured, and a drive force in the Y-axis direction isgenerated. That is, leveling table 52 is driven in the X-axis directionwith respect to Y stage 81 by X voice coil motor 54 a, as well as in theY-axis direction with respect to Y stage 81 by Y voice coil motors 54 band 54 c. In addition, by slightly changing the drive force generated byY voice coil motors 54 b and 54 c, leveling table 52 can also berotationally driven around the Z-axis (the Oz direction) with respect toY stage 81.

Inside leveling table 52, three Z voice coil motors (drawing omitted)are arranged that generate a drive force in the Z-axis direction.

That is, leveling table 52 is finely drivable in a non-contact manner indirections of six degrees of freedom (in the X, Y, Z, θx, θy, and θzdirections) by X voice coil motor 54 a, Y voice coil motors 54 b and 54c, and the Z voice coil motors (not shown) arranged inside levelingtable 52.

Referring back to FIG. 3, measurement table MTB is equipped with ameasurement table main body 59, and movers 62 and 64 that are fixed tothe surface of measurement table main body 59 on the +Y side in avertical arrangement, the movers having a rough sectional shape of aletter U whose longitudinal direction is the X-axis direction.

Mover 62 is equipped with a mover yoke that has a rough U-shape in a YZsection, and a permanent magnet group consisting of a plurality of setsof an N-pole permanent magnet and a S-pole permanent magnet alternatelyarranged at a predetermined distance along the X-axis direction on theinner surface (the upper and lower surface) of the mover yoke, and is ina state engaged with stator 61 previously described. In the inner spaceof the mover yoke of mover 62, an alternating magnetic field is formedalong the X-axis direction. Stator 61, for example, consists of anarmature unit that incorporates a plurality of armature coils arrangedat a predetermined distance along the X-axis direction. That is, stator61 and mover 62 constitute a moving magnet type X-axis linear motor LXthat drives measurement table MTB in the X-axis direction.

Mover 64 is equipped with a mover yoke that has a rough U-shape in theYZ section, and an N-pole permanent magnet and a S-pole permanent magnetarranged one by one on the inner surface (the upper and lower surface)of the mover yoke, and is in a state engaged with stator 63 previouslydescribed. In the inner space of the mover yoke of mover 64, a magneticfield is formed in the +Z direction (or the −Z direction). Stator 63 isequipped with an armature coil, which is arranged in an arrangementwhere the current flows only in the X-axis direction in a magnetic fieldformed by the N-pole magnet and the S-pole magnet. That is, mover 64 andstator 63 constitute a moving magnet type Y voice coil motor VY thatdrives measurement table MTB in the Y-axis direction.

As is obvious from the description so far, in the embodiment, Y-axislinear motors 82 to 85, X-axis linear motor 80, Z-tilt drive mechanism(not shown) that drives wafer table WTB, and each of the motorsdescribed above on measurement stage MST (54 a to 54 c, LX, VY, and theZ voice coil motor (not shown)) constitute stage drive system 124. Thevarious drive mechanisms that constitute stage drive system 124 operateunder the control of main controller 20 shown in FIG. 6.

Measurement table MTB is further equipped with measurement instrumentsfor performing various measurement related to exposure. Moreparticularly, as is shown in FIG. 3, on the upper surface of measurementtable main body 59, a plate 101 made of glass material such as Zerodur(brand name of Schott Corporation) or fused silica glass is arranged. Onplate 101, chrome is coated on substantially the entire surface, and onplate 101, an area for the measurement instruments, a high and lowreference reflecting surface area used when measuring reticletransmittance or the like, and a fiducial mark area on which a pluralityof fiducial marks are formed like the ones disclosed in, Kokai (JapaneseUnexamined Patent Application Publication) No. 5-21314 and thecorresponding U.S. Pat. No. 5,243,195 description, or in Kokai (JapaneseUnexamined Patent Application Publication) No. 10-050600 and thecorresponding U.S. Pat. No. 6,243,158 description, are arranged. Thefiducial mark area constitutes a measurement member. The surface ofplate 101 is a flat plane. As long as the national laws in designatedstates (or elected states), to which this international application isapplied, permit, the above disclosures of the publication and the U.S.Patent description are incorporated herein by reference.

In the area for the measurement instruments, patterning is performed,and various measurement aperture patterns are formed. As the measurementaperture patterns, for example, patterns such as an aerial imagemeasurement pattern (e.g., a slit-shaped aperture pattern), an irregularillumination measurement pinhole aperture pattern, an illuminancemeasurement aperture pattern, a wavefront aberration measurementaperture pattern, and the like are formed.

Inside measurement table main body 59 under the aerial image measurementpattern, a light-receiving system is arranged, which receives exposurelight (illumination light) IL via the aerial image measurement pattern,irradiated on plate 101 via projection optical system and the water. Thelight-receiving system constitutes an aerial image measurementinstrument, which measures the light intensity of an aerial image(projected image) of a pattern projected by projection optical systemPL. The details of the instrument are disclosed in, for example, Kokai(Japanese Unexamined Patent Application Publication) No. 2002-14005 andthe corresponding U.S. Patent Application Publication No. 2002/0041377Description. As long as the national laws in designated states (orelected states), to which this international application is applied,permit, the above disclosures of the publication and the U.S. Patentapplication description are incorporated herein by reference.

Further, inside measurement table main body 59 under the irregularillumination measurement pinhole aperture pattern, a light-receivingsystem that includes a light-receiving element is arranged. Thelight-receiving system including the light-receiving element constitutesan irregular illuminance measurement instrument, which has apinhole-shaped light-receiving section that receives illumination lightIL on the image plane of projection optical system PL. The details ofthe instrument are disclosed in, for example, Kokai (Japanese UnexaminedPatent Application Publication) No. 57-117238 and the corresponding U.S.Pat. No. 4,465,368 Description. As long as the national laws indesignated states (or elected states), to which this internationalapplication is applied, permit, the above disclosures of the publicationand the U.S. Patent description are incorporated herein by reference.

Further, inside measurement table main body 59 under the illuminancemeasurement aperture pattern, a light-receiving system that includes alight-receiving element is arranged. The light-receiving systemincluding the light-receiving element constitutes an illuminancemonitor, which has a light-receiving section of a predetermined areathat receives illumination light IL on the image plane of projectionoptical system PL via the water. The details of the instrument aredisclosed in, for example, Kokai (Japanese Unexamined Patent ApplicationPublication) No. 11-16816 and the corresponding U.S. Patent ApplicationPublication No. 2002/0061469 Description. As long as the national lawsin designated states (or elected states), to which this internationalapplication is applied, permit, the above disclosures of the publicationand the U.S. Patent application description are incorporated herein byreference.

Further, inside measurement table main body 59 under the wavefrontaberration measurement aperture pattern, for example, a light-receivingsystem that includes a microlens array is arranged. The light-receivingsystem including the microlens array constitutes a wavefront aberrationmeasurement instrument. The details of the instrument are disclosed in,for example, the pamphlet of International Publication No. WO99/60361,and the corresponding European Patent Publication No. 1,079,223Description. As long as the national laws in designated states (orelected states), to which this international application is applied,permit, the above disclosures of the publication and the European Patentdescription are incorporated herein by reference.

In FIG. 6, the aerial image measurement instrument, the irregularillumination measurement instrument, the illuminance monitor, and thewavefront aberration measurement instrument described above are shown asmeasurement instrument group 43.

In the embodiment, in response to the immersion exposure where wafer Wis exposed by exposure light (illumination light) IL via projectionoptical system PL and the water, the instruments used for measurement asin the illuminance monitor, the irregular illumination measurementinstrument, the aerial image measurement instrument, and the wavefrontaberration measurement instrument described above that use illuminationlight IL will receive illumination light IL via projection opticalsystem PL and the water. Therefore, a water-repellent coating may beperformed on the surface of plate 101. In addition, in each of themeasurement instruments described above, only a part of each measurementinstrument, such as the optical system, may be installed in measurementstage MST, or the whole instrument may be arranged in measurement stageMST. In addition, all of the aerial image measurement instrument, theirregular illumination measurement instrument, the illuminance monitor,and the wavefront aberration measurement instrument do not necessarilyhave to be equipped, and only a part of the instruments may be equippedas necessary.

The position of measurement stage MST (measurement table MTB) that hasthe arrangement described above is measured by interferometer system 118(refer to FIG. 6), which will be described later in the description.

In addition, as the holding member that holds projection unit PU, anoff-axis alignment system (hereinafter shortly referred to as ‘alignmentsystem’) ALG as is shown in FIG. 1 is arranged. As alignment system ALG,for example, a sensor of an FIA (Field Image Alignment) system based onan image-processing method is used. This sensor irradiates a broadbanddetection beam that does not expose the resist on the wafer on an objectmark, picks up an image of the object mark formed on the photodetectionsurface by the reflection light from the object mark and an image (notshown) of an index (an index pattern on an index plate arranged withinalignment system ALG) with a pick-up device (such as a CCD), and outputsthe imaging signals. Details on such a system are disclosed in, forexample, Kokai (Japanese Unexamined Patent Application Publication) No.2001-257157 and its corresponding U.S. Patent Application PublicationNo. 2001/0023918 description, Kokai (Japanese Unexamined PatentApplication Publication) No. 8-213306 and its corresponding U.S. Pat.No. 5,783,833 description, or the like. The imaging signals fromalignment system ALG are sent to main controller 20 in FIG. 6. As longas the national laws in designated states or elected states, to whichthis international application is applied, permit, the above disclosuresof the publications and the U.S. Patent application publicationdescription and the U.S. Patent are incorporated herein by reference.

As alignment system ALG, the system is not limited to the FIA system,and it is naturally possible to use an alignment sensor that irradiatesa coherent detection light on an object mark and detects the scatteredlight or diffracted light generated from the object mark, or a sensorthat detects two diffracted lights (for example, the same order)generated from an object mark that are made to interfere independently,or appropriately combined.

To members such as optical elements of alignment system ALG or holdingmembers of the optical elements that are arranged in the vicinity of themovement plane of wafer table WTB and have the risk of the liquidremaining on the members when the liquid disperses, a waterproof covermay be arranged. In addition, in a gap where there is a risk of theliquid entering inside alignment system ALG such as between an opticalelement and a holding member that holds the optical element, a sealmember such as an O-ring is arranged. Furthermore, the surface of theoptical members arranged in the vicinity of the movement plane of wafertable WTB, such as the surface of the optical element the tip (lowerend) of alignment system ALG and the surface of the mirror used by theinterferometer fixed to alignment system ALG, is coated with aliquid-repellent material, which not only prevents the water fromadhering, but also allows the operator to easily wipe off the water whenthe water adheres.

Furthermore, in exposure apparatus 100 of the embodiment, although it isomitted in FIG. 1, a multiple point focal position detection systembased on an oblique method including an irradiation system 90 a and aphotodetection system 90 b (refer to FIG. 6), similar to the onedisclosed in, for example, Kokai (Japanese Patent Unexamined ApplicationPublication) No. 6-283403 and the corresponding U.S. Pat. No. 5,448,332description, is arranged. In the embodiment, as an example, irradiationsystem 90 a is supported by suspension on the −X side of projection unitPU by a holding member that holds projection unit PU, whilephotodetection system 90 b is also supported by suspension under theholding member on the +X side of projection unit PU. That is,irradiation system 90 a and photodetection system 90 b, and projectionoptical system PL are attached to the same member, and the positionalrelation between the two is constantly maintained. As long as thenational laws in designated states or elected states, to which thisinternational application is applied, permit, the above disclosures ofthe publication and the U.S. Patent description are incorporated hereinby reference.

Next, the configuration and the operation of interferometer system 118will be described.

The end surfaces of wafer table WTB are mirror-polished on the −X sideand the −Y side, and as is shown in FIG. 2, reflection surfaces 17X and17Y are formed. In addition, the end surfaces of measurement table MTBare mirror-polished on the −X side, and the +Y side and the −Y side, andreflection surfaces 117X, and 117Y₁ and 117Y₂ are formed.

As is shown in FIG. 5, interferometer system 118 includes Y-axisinterferometers 16, 18, and 78, and X-axis interferometers 46, 66, and76.

Y-axis interferometers 16 and 18 both have measurement axes that areparallel to the Y-axis connecting the projection center of projectionoptical system PL (optical axis AX) and the detection center ofalignment system ALG. Y-axis interferometers 16 and 18 are bothmulti-axis interferometers that have at least three optical axes, andthe output values of each optical axis can be independently measured. Inaddition, X-axis interferometer 46 has measurement axes thatperpendicularly intersect with the measurement axes of Y-axisinterferometers 16 and 18 at the projection center of projection opticalsystem PL. In addition, X-axis interferometer 66 has measurement axesthat perpendicularly intersect with the measurement axes of Y-axisinterferometers 16 and 18 at the detection center of alignment systemAGL. X-axis interferometers 46 and 66 are both multi-axisinterferometers that have at least two optical axes, and the outputvalues of each optical axis can be independently measured. The outputvalues (measurement values) of the above four interferometers 16, 18,46, and 66 are sent to main controller 20 shown in FIG. 6. For example,in the state shown in FIG. 5, the interferometer beam (measurement beam)from Y-axis interferometer 16 is projected on reflection surface 117Y₁of measurement table MTB while the interferometer beam (measurementbeam) from Y-axis interferometer 18 is projected on reflection surface17Y of wafer table WTB, and the interferometer beam (measurement beam)from X-axis interferometer 46 is projected on reflection surface 117X ofmeasurement table MTB while the interferometer beam (measurement beam)from X-axis interferometer 66 is projected on reflection surface 17X ofwafer table WTB. And by respectively receiving the reflection beams ofthe measurement beams of the optical axis of each interferometer fromeach reflection surface, interferometers 16, 18, 46, and 66 measure thedisplacement for each optical axis in the measurement direction from thereference position (normally, a fixed mirror is arranged on the sidesurface of projection unit PU or off-axis alignment system ALG (refer toFIGS. 6 and 5), which serves as a reference plane) of each reflectionsurface.

In the case of FIG. 5, based on the output values of Y-axisinterferometer 18, main controller 20 measures not only the position ofwafer table WTB in the Y-axis direction (the Y position), but also therotation amount around the X-axis (pitching amount) and the rotationamount around the Z-axis (yawing amount). In addition, based on theoutput values of Y-axis interferometer 16, main controller 20 measuresnot only the position of measurement table MTB in the Y-axis direction(the Y position), but also the rotation amount around the X-axis(pitching amount) and the rotation amount around the Z-axis (yawingamount). Further, based on the output values (measurement values) ofX-axis interferometer 66, main controller 20 measures not only theposition of wafer table WTB in the X-axis direction (the X position),but also the rotation amount around the Y-axis (rolling amount).Furthermore, based on the output values (measurement values) of X-axisinterferometer 46, main controller 20 measures the X position and therolling amount of measurement table MTB.

As is obvious from FIG. 5, in the embodiment, the interferometer beamfrom Y-axis interferometer 18 is constantly projected on a movablemirror 17Y in the entire movement range of wafer stage WST on alignmentand on exposure, whereas the interferometer beam from Y-axisinterferometer 16 is constantly projected on a movable mirror 117Y₁ inthe entire movement range of measurement stage MST. Accordingly, for theY-axis direction, the Y position of stages WST and MST is controlled bymain controller 20 based on the measurement values of Y-axisinterferometers 18 and 16, except for the case when wafer stage WSTmoves to the wafer exchange position shown by the double-dotted line inFIG. 5.

Meanwhile, as is obvious from FIGS. 2 and 5, main controller 20 controlsthe X position of wafer table WTB (wafer stage WST) based on the outputof X-axis interferometer 46 within the range where only theinterferometer beam from X-axis interferometer 46 irradiates reflectionsurface 17X, while controlling the X position of measurement table MTB(measurement stage MST) based on the output of X-axis interferometer 46within the range where only the interferometer beam from X-axisinterferometer 46 irradiates reflection surface 117X. In addition, maincontroller 20 controls the X position of wafer table WTB (wafer stageWST) based on the output of X-axis interferometer 66 within the rangewhere only the interferometer beam from X-axis interferometer 66irradiates reflection surface 17X, while controlling the X position ofmeasurement table MTB (measurement stage MST) based on the output ofX-axis interferometer 66 within the range where only the interferometerbeam from X-axis interferometer 66 irradiates reflection surface 117X.

In addition, in the range including where the interferometer beams fromboth X-axis interferometer 46 and X-axis interferometer 66 irradiatereflection surface 17X, main controller 20 controls the X position ofwafer table WTB (wafer stage WST) on wafer alignment using X-axisinterferometer 66, whereas main controller 20 also controls the Xposition of wafer table WTB (wafer stage WST) on exposure using X-axisinterferometer 46. Accordingly, on both wafer alignment and on exposure,the X position of wafer table WTB (wafer stage WST) can be controlledwithout any Abbe errors.

The remaining X-axis interferometer 76 and Y-axis interferometer 78 areinterferometers that are used to control the position of wafer stage WSTwhen wafer stage WST is located in the vicinity of the wafer exchangeposition, which is outside the control of interferometers 46, 66, and18. Main controller 20 controls the position of wafer table WTB (waferstage WST) based on the measurement values of interferometers 76 and 78,during the period when the X position cannot be controlled based on theoutput values of interferometers 46, 66, and 18.

In addition, when measurement stage MST is at a waiting position furtheron the +Y side than the state in FIG. 5, the interferometer beams ofboth X-axis interferometer 66 and X-axis interferometer 46 do notirradiate reflection surface 117X. When measurement stage MST moves fromthis state in the −Y direction, immediately after the point when theinterferometer beam of X-axis interferometer 46 begins to irradiatereflection surface 117X from the state where it does not irradiatereflection surface 117X, main controller 20 resets X-axis interferometer46, which has not been used so far for control, and thereinafter,controls the X position of measurement table MTB (measurement stage MST)using X-axis interferometer 46. The other interferometers can performreset (seamless reset) operation using the output (measurement values)of adjacent interferometers. That is, immediately before resetting eachinterferometer, at the point where the measurement beams from adjacenttwo interferometers simultaneously begins to irradiate the reflectionsurface, by resetting (presetting) the interferometer subject to resetwith the measurement values of the X-axis interferometer or the Y-axisinterferometer that has been used for position control of wafer stageWST or measurement stage MST carried over, the position of wafer stageWST and measurement stage MST can be controlled using the interferometerthat has been reset without any problems. As a matter of course, whenmeasurement table MTB is at a waiting position, an interferometer formeasuring the X-axis position of measurement table MTB may be added.

Furthermore, in exposure apparatus 100 of the embodiment, the waferexchange position (the loading position) is decided at a position in themovable range of wafer stage WST in the vicinity of the edge section onthe +X side and the vicinity of the edge section on the −Y side, andreticle alignment and baseline measurement of alignment system ALG areto be performed when wafer stage WST is located at the wafer exchangeposition. When wafer stage WST is at the wafer exchange position,because the interferometer beam (measurement beam) from Y-axisinterferometer 18 irradiates reflection surface 117Y₂ of measurementtable MTB, main controller 20 resets the measurement values of Y-axisinterferometer 18 prior to the irradiation. And then, main controller 20begins the series of operations related to reticle alignment andbaseline measurement of alignment system ALG, while controlling theposition of measurement table MTB using the Y-axis interferometer 18that has been reset and X-axis interferometer 46. This is because bymeasuring the baseline using fiducial mark area FM on measurement tableMTB previously described while controlling the position of measurementtable MTB using Y-axis interferometer 18, which is used for measuringthe position of wafer table WTB (wafer stage WST) on wafer alignment andexposure, and by performing position control of wafer table WTB onexposure using the baseline that has been measured, position errorscaused by the difference in interferometers used for control can be keptfrom occurring.

In the embodiment, on reticle alignment, main controller 20 controls theopen/close operation of each valve in liquid supply unit 88 and liquidrecovery unit 92 of immersion mechanism 132 as is previously described,and water Lq is constantly filled in the space between tip lens 91 ofprojection optical system PL and fiducial mark area FA of measurementtable MTB. Then, main controller 20 detects the relative position (afirst relative position) between at least a pair of reticle alignmentmarks on reticle R and at least a pair of first fiducial marks onfiducial mark area FM, using reticle alignment detection systems RAa andRAb, and then after the detection, moves measurement table MTB based onthe design values of the baseline until fiducial mark area FM comesdirectly under alignment system ALG. Then, in a state where water Lqdoes not exist on fiducial mark area FM, main controller 20 detects asecond fiducial mark on fiducial mark area FM using alignment systemALG, and the relative position (a second relative position) between thedetection center of alignment system ALG and the second fiducial mark.Then, main controller 20 calculates the baseline of alignment systemALG, based on the first relative position, the second relative position,the design values of the baseline, and the positional relation betweenthe pair of first fiducial marks and the second fiducial mark.

In the embodiment, the three Y-axis interferometers 16, 18, and 78 andthe three X-axis interferometers 46, 66, and 76 constituteinterferometer system 118. However, the configuration of such aninterferometer system is a mere example, and the present invention isnaturally not limited to this.

Referring back to FIG. 1, in exposure apparatus 100, a carrier arm 70 isarranged that carries wafer W to wafer stage WST. Carrier arm 70 may bean arm by a slide method or a robot arm of a horizontal multijoint type,as long as it carries the wafer between a pre-alignment unit (not shown)that detects the center position and the rotation angle of the wafer andwafer stage WST located at the wafer exchange position. In theembodiment, a carrier system 72 (refer to FIG. 6) that carries the waferto wafer stage WST is configured, including carrier arm 70, thepre-alignment unit (not shown), a carrier section that carries the waferto the pre-alignment unit from the outside, and the like.

FIG. 6 shows the main configuration of a control system of exposureapparatus 100. The control system is mainly composed of main controller20, which is made up of a microcomputer (or a workstation) that hasoverall control over the entire apparatus.

As is described above, the position of wafer table WTB and measurementtable MTB within the XY plane can be measured at a resolution of 0.5 to1 nm by each interferometer of interferometer system 118, however,because there are no reference marks for position measurement onliquid-repellent plate 50 in the embodiment, for example, it becomesdifficult to restore wafer table WTB to a reference state (or to a statebefore the last interferometer beam moves away from wafer table WTB)after at least one interferometer has been reset, after theinterferometer beams from all the Y-axis interferometers or all theX-axis interferometers move off the reflection surface of wafer tableWTB. In addition, in the embodiment, because the periphery ofliquid-repellent plate 50 projects outside wafer table WTB (reflectionsurface), it is difficult to control the position of wafer table WTB sothat the outer periphery edge of liquid-repellent plate 50 does nottouch other members. It is difficult to control the position of wafertable WTB, especially immediately after when liquid-repellent plate 50is exchanged. In consideration of such points, in exposure apparatus 100of the embodiment, main controller 20 measures the position ofliquid-repellent plate 50 in the manner described below, and controlsthe position of wafer table WTB based on the measurement results.

FIG. 7 shows an example of a flowchart of a processing algorithm of (theCPU inside) main controller 20 when the restoring operation of wafertable WTB to a reference state is performed, after liquid-repellentplate 50 has been exchanged. The processing algorithm is to begin whenwafer stage WST moves to the position shown in FIG. 8, immediately afterthe measurement values of interferometer have been reset. At this stage,the position of wafer table WTB is controlled by main controller 20based on the measurement values of interferometers 17 and 76. Therotation error of wafer table WTB itself in the Oz direction is to besmall enough to be ignored. In addition, as is previously described,when wafer table WTB (wafer stage WST) or the like moves, seamlesspreset of the measurement values of the interferometers previouslydescribed is performed, however, in the description of the processingalgorithm below, in order to simplify the description, the descriptionor the like related to the seamless preset of the measurement values ofthe interferometers will be omitted, and the position of wafer stage WST(wafer table WTB) is to be controlled on a stage coordinate system (X,Y) set by the measurement axes of interferometer system 118. There areno serious problems to such a premise, because the measurement values ofadjacent X-axis interferometers and Y-axis interferometers aresequentially carried over by the seamless preset.

First of all, in step 202 in FIG. 7, a counter value n of a firstcounter that shows the measurement point number on the outer peripheryedge of liquid-repellent plate 50 is initialized to 1 (n←1). In thiscase, as the number of areas subject to measurement, N, or to be moreprecise, 4 areas in this case, that is, the points in the center of eachedge of liquid-repellent plate 50 vertically and horizontally are to beset.

In the next step, step 204, wafer stage WST is moved so that the n^(th)(in this case, the 1^(st)) measurement point on the outer periphery edgeof liquid-repellent plate 50 is positioned directly under alignmentsystem ALG, while the position of wafer table WTB is measured usinginterferometer system 118.

FIG. 9A shows the situation when the position of the 1^(st) measurementpoint on the outer periphery edge of liquid-repellent plate 50 on wafertable WTB (wafer stage WST) is set directly under alignment system ALG.In FIGS. 9B to 9D, the reference ALG′ indicates the imaging field ofalignment system ALG.

Referring back to FIG. 7, in step 206, the n^(th) (in this case, the1^(st)) measurement point on the outer periphery edge is picked up usingalignment system ALG, and the imaging data (imaging signals) is loaded,along with the measurement values of interferometer system 118 at thispoint. Both data are made to correspond with each other, and are storedin memory (not shown).

In the next step, step 208, the judgment is made whether or not countervalue n of the first counter has reached N (in this case, N=4) or not.In this case, since n=1, the judgment here is denied, and the procedurethen moves to step 210 where counter value n of the first counter isincremented by 1, and then the procedure returns to step 204.

Hereinafter, the loop processing of steps 204→206→208→210 is repeateduntil the judgment in step 208 is affirmed. Accordingly, from theposition shown in FIG. 9A, wafer table WTB is sequentially positioned toeach of the positions shown in FIGS. 9B, 9C, and 9D, and the outerperiphery edge of liquid-repellent plate 50 is picked up using alignmentsystem ALG, and the imaging data (imaging signals) is stored in memorywith the position information (the measurement values of interferometersystem 118) of wafer table WTB corresponding to the imaging data.

Then, when loading of the imaging data or the like of the edge on the −Xside of liquid-repellent plate 50 shown in FIG. 9D is completed, thejudgment in step 208 turns positive, and the procedure then moves tostep 212.

In step 212, the position information of the 1^(st) to N^(th) (in thiscase, the 4^(th)) measurement point on the outer periphery ofliquid-repellent plate 50 is obtained by an image processing method,based on the imaging data (imaging results) of each edge stored memoryand the corresponding measurement results of interferometer system 118.

In the next step, step 214, based on the position information of theouter periphery edge at the obtained N points (in this case, 4 points),the position information or the like of liquid-repellent plate 50 suchas for example, a predetermined reference point (e.g., the center point)of liquid-repellent plate 50 on the stage coordinate system (X, Y) iscalculated, and then after such calculation, the processing in step 216is performed when necessary, and then the processing shown in FIG. 7 iscompleted.

Then, based on the position information of the outer periphery edge ofliquid-repellent plate 50 or the position information ofliquid-repellent 50 measured in the matter described above, maincontroller 20 performs position control of wafer table WTB. For example,main controller 20 controls at least one of the position of wafer tableWTB (wafer stage WST) and the position of measurement stage MST basedthe position information of the outer periphery edge of liquid-repellentplate 50 or the position information of liquid-repellent 50, so that theouter periphery edge of liquid-repellent plate 50 does not touchmeasurement stage WST.

In the case of performing the processing in step 216 above, the positioninformation of a part of the wafer holder is to be obtained as in theposition information of liquid-repellent plate 50 previously described,and based on the position information and the position information ofliquid-repellent plate 50 obtained in step 212 or step 214 above, theposition relation between wafer holder WH (wafer table WTB) and theliquid-repellent plate is to be calculated.

In the case, for example, the Oz rotation of liquid-repellent plate 50is also measured, the measurement points on the outer periphery edge ofliquid-repellent plate 50 are to be set at a plurality of points on atleast one edge (that is, 5 or more in total), and then the processing isto be performed according to a flow chart similar to the one in FIG. 7previously described. FIG. 10A shows the situation where wafer table WTBis moved when sequentially measuring the position information of theplurality of measurement points on the edge of liquid-repellent plate 50on the +Y side edge section. And, in this case, in step 214 previouslydescribed, as the position information of liquid-repellent plate 50, inaddition to the position information of the reference point describedabove, the θz rotation of the edge (that is, the rotation angle ofliquid-repellent plate 50 with respect to the stage coordinate system)may also be calculated based on position information of at least twopoints on the edge where the plurality of points subject to measurementare set.

In this case, the θz rotation of each edge can be obtained by settingthe plurality of measurement points on each of the four edges ofliquid-repellent plate 50. For example, as in the pattern shown in FIG.10B, three measurement points can be set on each of the four edges andthe average value of the θz rotation for each edge that has beenobtained can be obtained. In actual, imaging field ALG′ of alignmentsystem ALG is fixed and wafer table WTB moves, however, FIG. 10B showsas if imaging field ALG′ moves with respect to wafer table WTB, which isfixed for the sake of convenience.

In the embodiment, the outer periphery edge of liquid-repellent plate 50is imaged at a plurality of points including two points symmetry to thevirtual center of liquid-repellent plate 50. The imaging places,however, is not limited to this, and does not have to be two placessymmetry to the virtual center of liquid-repellent plate 50. Forexample, the outer periphery edge may be imaged at a plurality of pointsincluding one point on one edge of the outer periphery ofliquid-repellent plate 50 and another point on the opposite edge of theone edge. In this case, because a substantially symmetric image of atleast two outer periphery edges that oppose each other can be obtained,position information (such as the center position) of liquid-repellentplate 50 can be calculated.

Next, a series of processing performed in exposure apparatus 100 of theembodiment from when the liquid-repellent plate on wafer table WTB isexchanged until the next exchange of the liquid-repellent plate isperformed is described, based on the flowchart in FIGS. 11 and 12 thatshow the processing algorithm of (the CPU inside) main controller 20while referring to other drawings as appropriate. In the description ofthe processing algorithm below, descriptions on seamless preset of themeasurement values of the interferometers previously described will beomitted, and the position of wafer stage WST (wafer table WTB) is to becontrolled on the stage coordinate system (X, Y) set by the measurementaxes of interferometer system 118.

First of all, in step 222 in FIG. 11, a subroutine for measuring theposition information of the inner periphery edge of the opening of theliquid-repellent plate is performed.

In the subroutine of step 222, firstly, in step 302 in FIG. 13, acounter value m of a second counter that shows the order of themeasurement points of the inner periphery edge of opening 50 a ofliquid-repellent plate 50 is initialized to 1 (m←1). As the measurementpoints, M points, or in this case, eight points, which are intersectingpoints of eight lines that radially extend in eight directions includingthe horizontal and vertical directions at a center angle of 45° from thecenter of opening 50 a of liquid-repellent plate 50 and the innerperiphery edge, are decided.

In the next step, step 304, wafer table WTB (wafer stage WST) is movedso that the m^(th) (in this case, the 1^(st)) measurement point on theinner periphery edge of opening 50 a of liquid-repellent plate 50 ispositioned directly under alignment system ALG, while the position ofwafer table WTB is measured using interferometer system 118.

FIG. 15A shows the situation when the position of the 1^(st) measurementpoint is set within the imaging field of alignment system ALG. In FIGS.15A to 15D and FIGS. 16A to 16D, the reference ALG′ indicates theimaging field of alignment system ALG.

In the next step, step 306, the m^(th) (in this case, the 1^(St))measurement point on the inner periphery edge of opening 50 a is pickedup using alignment system ALG, and the imaging data (imaging signals) isloaded, along with the measurement values of interferometer system 118at this point. Both data are made to correspond with each other, and arestored in memory (not shown).

In the next step, step 308, the judgment is made whether or not countervalue m of the second counter has reached M (in this case, M=8) or not.In this case, since m=1, the judgment here is denied, and the procedurethen moves to step 310 where counter value m of the second counter isincremented by 1, and then the procedure returns to step 304.

Hereinafter, the loop processing of steps 304→306→308→310 is repeateduntil the judgment in step 308 is affirmed. Accordingly, from theposition shown in FIG. 15A, wafer table WTB is sequentially positionedto each of the positions shown in FIGS. 15B, 15C, 15D, 16A, 16B, 16C,and 16D, and the inner periphery edge of opening 50 a ofliquid-repellent plate 50 is picked up using alignment system ALG, andthe imaging data (imaging signals) is stored in memory with the positioninformation (the measurement values of interferometer system 118) ofwafer table WTB corresponding to the imaging data.

Then, when loading of the imaging data or the like of the 8^(th)measurement point on the inner periphery edge of opening 50 a shown inFIG. 16D is completed, the judgment in step 308 turns positive, and theprocedure then moves to step 314. As is modeled in FIG. 17A, the imagingdata of the eight points on the inner periphery edge of opening 50 a andthe position information of wafer table WTB corresponding to the imagingdata are stored in memory. In actual, imaging field ALG′ of alignmentsystem ALG is fixed and wafer table WTB moves, however, FIG. 17A showsas if imaging field ALG′ moves with respect to wafer table WTB, which isfixed for the sake of convenience.

In step 314, after the position information of the 1^(st) to the M^(th)(in this case, the 8^(th)) measurement points on the inner peripheryedge of opening 50 a of liquid-repellent plate 50 is obtained by theimage processing method, based on the imaging data (imaging results) ofthe M points (eight, in this case) on the inner periphery edge ofopening 50 a and measurement results of interferometer system 118corresponding to the imaging data that are stored in memory, theprocessing in the subroutine is completed, and the subroutine returns tostep 224 (refer to FIG. 11) in the main routine.

In step 224, based on the position information of the M points (in thiscase, eight points) on the inner periphery edge of opening 50 a, forexample, position information of opening 50 a of liquid-repellent plate50 such as the position information of a predetermined reference point(e.g., the center point) of opening 50 a on the stage coordinate system(X, Y) is calculated (that is, based on the position information of theinner periphery edge, the position relation between the stage coordinatesystem set by interferometer system 118 and opening 50 a is decided) bythe least squares method or the like, and then the procedure then moveson to step 226.

In step 226, based on the position information of the M points (in thiscase, eight points) on the inner periphery edge of opening 50 adescribed above, the shape information (the shape information includesat least the roundness of opening 50 a) of opening 50 a ofliquid-repellent plate 50 is calculated by a predetermined calculation.Roundness, in this case, refers to an evaluation amount that shows thedeviation of opening 50 a from an ideal perfect circle, and it can bedefined as the difference between the maximum radius and the minimumradius of the outline of opening 50 a with respect to the center ofopening 50 a. The center of the circle, which is to be the reference ofsuch roundness, may be a center calculated in one of the methodsdescribed below.

a. minimum zone circle (MZC) method: the center where when twoconcentric circles are positioned enclosing the outline of the opening,the radial departure of the concentric circles becomes a minimum

b. least squares mean circle (LSC) method: the center of a least squaresmean circle (a circle whose sum of the squares of the deviation from areference circle is minimized)

c. minimum circumscribed circle (MCC) method: the center of a smallestpossible circle which can be fitted around the outline of the opening

d. maximum inscribed circle (MIC) method: the center of a circle ofmaximum radius that is totally enclosed by the outline of the opening.

In the next step, step 228, the judgment is made whether or not theroundness calculated in step 226 above is below a first threshold valueor not. A value within in the limit of use as a liquid-repellent plateis decided as the first threshold value. Accordingly, in the case thejudgment in step 228 is denied, then it means that liquid-repellentplate 50 is a plate whose level of roundness of the opening formed isinsufficient and cannot be used in the exposure apparatus. Therefore,the procedure moves to step 264 in FIG. 12 where a notice, such as, forexample, ‘liquid-repellent plate defect (exchange required)’ is shown onthe display (not shown) so that the liquid-repellent plate defect isnotified to the operator, and then the processing of the routine iscompleted. Then, by confirming the notice (display), the operator stopsthe operation of exposure apparatus 100, and then manually performs theexchange of liquid-repellent plate 50. In the case the exposureapparatus is equipped with a robot that can be used for exchangingliquid-repellent plate 50, main controller 20 can show the exchangeperiod on the display, as well as stop the operation of the apparatusand then exchange the liquid-repellent plate, using the robot.

Meanwhile, in the case the judgment in step 228 is affirmed, theprocedure then moves to the next step, step 230 where the judgment ofwhether the roundness calculated in step 226 above is below a secondthreshold value or not. And, in the case the judgment is denied, theprocedure then moves to step 234 where a tool wafer W1 (refer to FIG.17B) is loaded onto wafer holder WH inside opening 50 a ofliquid-repellent plate 50, using carrier arm 70 in carrier system 72 andcenter-ups 34 a to 34 c previously described. Then, the procedure movesto step 236 where a subroutine of measuring position information of theouter periphery edge of the object in the opening is performed. In thiscase, tool wafer W1 is a tool wafer that has a diameter (outer diameter)slightly smaller than that of wafer W, which is the object subject toprocessing used in device manufacturing. On the contrary, in the casethe judgment is affirmed in step 230, the procedure then moves to step232 where wafer W is loaded on wafer WH inside opening 50 a ofliquid-repellent plate 50, using carrier arm 70 in carrier system 72 andcenter-ups 34 a to 34 c previously described. Then, the procedure moveson to the subroutine in step 236. On this loading, the position of atleast one of wafer table WTB and carrier arm 70 is controlled, based onthe position information of the inner periphery edge of opening 50 aobtained in step 222 or the position information f opening 50 a obtainedin step 224.

As is described, the second threshold value is decided for determiningwhether to choose tool wafer W1 or wafer W. In the case the roundness ofopening 50 a is high, then wafer W used in device manufacturing can beloaded without any problems on wafer holder WH inside opening 50 a,however, in the case the roundness of opening 50 a is low, when wafer Wis to be loaded onto wafer WH inside opening 50 a, the possibility ishigh of wafer W to come into contact with the inner periphery edge ofopening 50 a, and the loading may be difficult. Accordingly, in thelatter case, tool wafer W1 whose diameter is smaller than wafer W is tobe loaded on wafer holder WH.

In the subroutine in step 236, first of all, in step 322 in FIG. 14, acount value k of a third counted that shows the order of the measurementpoints of the outer periphery edge of the object inside opening 50 a(tool wafer W1 or wafer W, hereinafter, representatively referred to astool wafer W1 as appropriate) is initialized to 1 (k←1). As themeasurement points, K points, or in this case, eight points, which areintersecting points of eight lines that radially extend in eightdirections including the horizontal and vertical directions at a centerangle of 45° from the center of tool wafer W1 and the outer peripheryedge of tool wafer W1, are decided.

In the next step, step 324, wafer table WTB (wafer stage WST) is movedso that the k^(th) (in this case, the 1^(st)) measurement point on theouter periphery edge of tool wafer W1 within opening 50 a ofliquid-repellent plate 50 is positioned directly under alignment systemALG, while the position of wafer table WTB is measured usinginterferometer system 118.

In the next step, step 326, the k^(th) (in this case, the 1^(st))measurement point on the outer periphery edge of tool wafer W1 is pickedup using alignment system ALG, and the imaging data (imaging signals) isloaded, along with the measurement values of interferometer system 118at this point. Both data are made to correspond with each other, and arestored in memory (not shown).

In the next step, step 328, the judgment is made whether or not countervalue k of the third counter has reached K (in this case, K=8) or not.In this case, since k=1, the judgment here is denied, and the procedurethen moves to step 330 where counter value k of the third counter isincremented by 1, and then the procedure returns to step 324.

Hereinafter, the loop processing of steps 324→326→328→330 is repeateduntil the judgment in step 328 is affirmed. Accordingly, as is shown inFIG. 17B, wafer table WTB is sequentially positioned to a position whereeach of the eight measurement points is positioned within imaging fieldALG′ of alignment system ALG, and the outer periphery edge of tool waferW1 is picked up at each position-setting position using alignment systemALG, and the imaging data (imaging signals) is stored in memory with theposition information (the measurement values of interferometer system118) of wafer table WTB corresponding to the imaging data.

Then, when the imaging data of the eighth point of the outer peripheryedge has been loaded, the judgment in step 328 is affirmed, and then theprocedure moves to step 332.

In step 332, after the position information of the 1^(st) to the K^(th)(in this case, the 8^(th)) measurement points on the outer peripheryedge of the object inside opening 50 a is obtained by the imageprocessing method, based on the imaging data (imaging results) of the Kpoints (eight, in this case) on the outer periphery edge of the objectinside opening 50 a and measurement results of interferometer system 118corresponding to the imaging data that are stored in memory, theprocessing in the subroutine is completed, and the subroutine returns tostep 240 (refer to FIG. 12) in the main routine.

In step 240, the position relation between the inner periphery edge ofopening 50 a and the object inside opening 50 a is obtained. Morespecifically, based on the position information of the K points (in thiscase, eight points) on the outer periphery edge of the object in opening50 a, such as, based on the position information of the object (positioninformation of the center of the object on the stage coordinate system(X, Y)) calculated by the least squares method or the like and theposition information of opening 50 a ((position information of thecenter of opening 50 a on the stage coordinate system (X, Y)) ofliquid-repellent plate 50 obtained in step 224 previously described, theposition relation between the inner periphery edge of opening 50 a andthe object within 50 a, such as the information on deviation between thecenter of opening 50 a and the center of the object (tool wafer W1 orwafer W).

In the next step, step 242, wafer stage WST is moved to the waferexchange position, and the object (tool wafer W1 or wafer W) is unloadedfrom wafer holder WH, using carrier arm 70 of carrier system 72 andcenter-ups 34 a to 34 c.

In the next step, step 244, exposure of a lot (wafers of a predeterminednumber) begins.

In step 244, wafer W serving as a first substrate subject to exposure onwhich pre-alignment (center detection and rotation adjustment) has beenperformed by the pre-alignment unit (not shown) constituting a part ofcarrier system 72 is carried using carrier arm 70, to a position abovewafer stage WST, located at the wafer exchange position. Then, by takinginto consideration the information on position relation of the innerperiphery edge of opening 50 a and the object inside opening 50 aobtained in step 240 described above, such as the information ondeviation previously described, the position relation between carrierarm 70 and wafer stage WST is adjusted and wafer W is loaded onto waferholder WH arranged on wafer table WTB from carrier arm 70. In this case,the adjustment of the position relation between carrier arm 70 and waferstage WST is performed by adjusting both or either one of the positionsof carrier arm 70 and wafer stage WST. Accordingly, by loading wafer Wafter the position relation of carrier arm 70 and wafer stage WST onloading wafer W is adjusted, normally, it becomes possible to load waferW on wafer holder WH inside the inner periphery edge of opening 50 a ofliquid-repellent plate 50 above wafer table WTB (inside the depressedsection on the upper surface of wafer table WTB) in a manner that theouter periphery edge of wafer W and the inner periphery edge (the innerperiphery edge of depressed section 140 on the upper surface of wafertable WTB) of liquid-repellent plate 50 a do not come into contact, andthe outer periphery edge of wafer W and the inner periphery edge ofopening 50 a are also distanced at a predetermined value, such as, lessthan around 0.3 mm.

In the next step, step 246, wafer stage WST is moved so that it islocated under alignment system ALG.

In the next step, step 248, the distance between the inner peripheryedge of opening 50 a of liquid-repellent plate 50 and (the outerperiphery of) wafer W is measured across the entire circumference ofwafer W in the same procedure as the position measurement of the outerperiphery edge of wafer W and the like previously described, usingalignment system ALG. In this case, it is especially important toarrange at least a plurality sets of measurement points that are indirections different from that of the eight directions from the wafercenter on measuring the outer periphery edge or the wafer or the innerperiphery edge of the opening as is previously described.

Then, in the next step, step 250, the judgment of whether the distanceacross the entire circumference of the wafer is within a permissiblerange or not is made, based on the measurement results in step 248above. As is previously described, normally, because wafer W is loadedon wafer holder WH so that the outer periphery edge of wafer W and theinner periphery edge (the inner periphery edge of depressed section 140on the upper surface of wafer table WTB) of liquid-repellent plate 50 ado not come into contact, and the outer periphery edge of wafer W andthe inner periphery edge of opening 50 a are also distanced at, such as,less than around 0.3 mm, the judgment made in step 250 is affirmative,and the procedure then moves on to the next step, step 252.

Meanwhile, the judgment made in step 250 based on the measurementresults of step 248 may turn out to be negative, due to the outerdiameter error or the like of wafer W. Accordingly, in the case thejudgment in step 250 results negative, the procedure then moves to step242 previously described, and the first wafer W is unloaded from thewafer holder. Then, the operations of steps 224, 246, 248, and 250 areperformed on the second wafer W as is previously described. In thiscase, in step 244, when the second wafer W is loaded onto the waferstage (wafer holder), the position relation between the carrier arm andthe wafer stage is adjusted taking into consideration the measurementresults related to the first wafer W obtained in step 248. And, when thejudgment related to the second wafer W in step 250 is affirmed, theprocedure then moves to step 252.

In step 252, alignment marks on wafer W are detected using alignmentsystem ALG, and by detecting the position information of the alignmentmarks based on the detection results and the measurement values ofinterferometer system 118 on detection, wafer alignment, such asEnhanced Global Alignment (EGA), is performed.

In the next step, step 254, based on the position information of aplurality of shot areas on wafer W obtained as the results of the waferalignment referred to above, the latest baseline measurement results ofalignment system ALG, and the like, the movement operation in betweenshots in order to move wafer stage WST to the scanning starting position(acceleration starting position) of each shot area and the scanningexposure operation for transferring the pattern formed on reticle R ontoeach shot area by the scanning exposure method are repeatedly performed,and exposure of a plurality of shot areas on wafer W by thestep-and-scan method is performed. On this exposure, water is constantlysupplied to the space below tip lens 91 of projection optical system PL.

In the next step, step 256, the judgment of whether or not exposure ofall the wafers in one lot has been completed is made. And, when thejudgment turns out to be negative, the procedure then moves on to step262 where wafer W held on wafer holder WH of wafer table WTB that hasbeen exposed is exchanged with a new wafer, and then the procedure movesto step 252 where the processing in the loop of steps 252→254→256→262 ishereinafter repeated until the judgment in step 256 is affirmed.

Meanwhile, in the case the judgment in step 256 referred to above isaffirmed, the procedure then moves on to step 258.

In the next step, step 258, the judgment of whether or not the timing ofexchange of the liquid-repellent plate is due is made, referring to, forexample, the irradiation record of illumination light IL. In theembodiment, the relation between the deterioration of thewater-repellent coating on the surface of liquid-repellent plate 50 andthe integrated energy amount irradiated on the surface ofliquid-repellent plate 50 is obtained in advance by experiment, andbased on the relation and the irradiation record of illumination lightIL, the judgment that the timing of exchange of liquid-repellent plate50 is due is to be made just before the water-repellent coatingdeteriorates.

Then, in the case when the judgment is made that the timing of exchangeis due, the procedure then moves to step 264 previously described, andwhen the judgment is made that the timing has not come yet, theprocedure moves on to the processing of the next lot.

In the manner described above, the series of processing from exchangingthe liquid-repellent plate to the next exchange is executed.

As is obvious from the description so far, in the embodiment, maincontroller 20, or to be more precise, the CPU inside main controller 20and the software executed by the CPU make up at least a part of eachunit such as an outer periphery edge position obtaining unit, an innerperiphery edge position obtaining unit, a decision-making unit, a shapecalculation unit, an object outer periphery edge position obtainingunit, a distance measurement unit, a stage controller, a controller, andthe like. However, it is a matter of course that at least a part of thecomponents made up by such software may also be constituted by hardware.

As is described above, according to exposure apparatus 100 of theembodiment, main controller 20 detects a part of liquid-repellent plate50 using alignment system ALG while measuring the position of wafertable WTB (wafer stage WST) on which liquid-repellent plate 50 isdetachably installed using interferometer system 118. And then, based onthe detection results and the measurement results of interferometersystem 118 corresponding to the detection results, the positioninformation of the outer periphery edge of liquid-repellent plate 50 isobtained (steps 204 to 210). Therefore, it becomes possible to controlthe position of liquid-repellent plate 50, or in other words, theposition of wafer table WTB (wafer stage WST) on the movement coordinatesystem (stage coordinate system) set by the interferometer system basedon the position information of the outer periphery edge ofliquid-repellent plate 50, even if there are no marks for positionmeasurement on wafer table WTB (wafer stage WST) as in the embodiment.

In addition, in the case the outer periphery of liquid-repellent plate50 projects outward than wafer table WTB as in the embodiment, theposition of wafer table WTB wafer stage WST) can be controlled so thatthe outer periphery edge of liquid-repellent plate 50 does not touchother members (such as measurement stage MST).

It is also a matter of course that the position information of the outerperiphery of liquid-repellent plate 50 can be obtained in the mannerdescribed above, even in the case when marks for position measurementare arranged on wafer table WTB (wafer stage WST) or liquid-repellentplate 50 or when the outer periphery of liquid-repellent plate 50 doesnot project outward than wafer table WTB.

In addition, according to exposure apparatus 100 of the embodiment, maincontroller 20 detects a part of liquid-repellent plate 50 usingalignment system ALG while measuring the position of wafer table WTBusing interferometer system 118. And then, based on the detectionresults and the measurement results of interferometer system 118corresponding to the detection results, the position information of theinner periphery edge of opening 50 a of liquid-repellent plate 50 isobtained (step 2 22). Therefore, it becomes possible to calculate theposition and the shape of opening 50 a (refer to steps 224 and 226),based on the position information of the inner periphery edge.

In addition, in exposure apparatus 100 of the embodiment, in the case,for example, when the roundness is below the second threshold value,main controller 20 loads wafer W on wafer holder WH (step 232) insideopening 50 a of liquid-repellent plate 50 on wafer stage WST (wafertable WTB) via carrier system 72, based on the position information ofthe inner periphery edge of opening 50 a of liquid-repellent plate 50.Accordingly, it becomes easier to load wafer W inside opening 50 a ofliquid-repellent plate 50 on wafer stage WST than when the informationrelated to the inner periphery edge of opening 50 a of liquid-repellentplate 50 is not take into consideration.

In addition, in exposure apparatus 100 of the embodiment, in the casethe position relation between the inner periphery edge of opening 50 aand the object inside opening 50 a (tool wafer W1 or wafer W) isobtained (refer to step 240), main controller 20 loads the waferadjusting the position relation of carrier arm 70 and the wafer table bycontrolling at least either wafer table WTB or carrier arm 70 of carriersystem 72 taking into consideration the position relation referred toabove, when carrying wafer W to wafer table WTB by carrier system 72(refer to step 244). Accordingly, based on the position relation thathas been obtained, it becomes possible to load the wafer within thedepressed section 140 of wafer table WTB, that is, within the innerperiphery edge of opening 50 a of liquid-repellent plate 50 at a desiredposition relation. In this case, it becomes possible to load wafer W onwafer holder WH within the inner periphery edge (within the depressedsection on the upper surface of wafer table WTB) of opening 50 a ofliquid-repellent plate 50 above wafer table WTB, so that the outerperiphery edge of wafer W and the inner periphery edge (the innerperiphery edge of the depressed section on the upper surface of wafertable WTB) of liquid-repellent plate 50 a do not come into contact, andthe outer periphery edge of wafer W and the inner periphery edge ofopening 50 a are also distanced at a predetermined value, such as, lessthan around 0.3 mm.

In the operations described referring to FIGS. 11 and 12, when toolwafer W1 is mounted on the wafer holder, the first threshold value andthe second threshold value are set with respect to the shape (roundness)of opening 50 a. However, the judgment of whether to mount tool wafer W1or not can be made using only one of the threshold values. In this case,tool wafer W1 can be a wafer with a smaller diameter than that of waferW subject to exposure, or a wafer that has substantially the samediameter as wafer W subject to exposure.

In addition, in the operations described referring to FIGS. 11 and 12,tool wafer W1 is mounted on the wafer holder after the shape informationof opening 50 a is obtained, however, such a process of obtaining shapeinformation can be omitted. In this case as well, a wafer with a smallerdiameter than that of wafer W subject to exposure or a wafer that hassubstantially the same diameter as wafer W subject to exposure can beused as tool wafer W1.

In addition, in the operations described referring to FIGS. 11 and 12,tool wafer W1 is mounted on the wafer holder after the positioninformation and the shape information of opening 50 a are obtained,however, obtaining the position information and the shape information ofopening 50 a can be omitted, and the position information of the openingand the position relation (including the distance) of the innerperiphery edge of the opening and the outer periphery edge of tool waferW1 can be obtained, after tool wafer W1 is mounted on the wafer holder.As a matter of course, the shape information of opening 50 a can beobtained if necessary. In this case, as tool wafer W1, it is desirablefor the wafer to be a wafer whose diameter is smaller than that of waferW subject to exposure, however, the wafer may be a wafer ofsubstantially the same diameter as wafer W subject to exposure.

In addition, in the operations described referring to FIGS. 11 and 12,the position relation (distance) between the inner periphery edge ofopening 50 a and wafer W is measured when wafer W serving as a firstsubstrate subject to exposure is mounted on the wafer holder. However,in the case wafer W serving as the substrate subject to exposure can beloaded onto the predetermined position within opening 50 a, themeasurement operation (steps 246, 248, and 250) can be omitted.

In addition, in the operations described referring to FIGS. 11 and 12,in step 258, the judgment is made whether or not to exchangeliquid-repellent plate 50 after the exposure processing of one lot hasbeen completed. Step 258, however, may be omitted, and the judgment canbe made at a predetermined time interval, or the liquid-repellent platemay be exchanged after the elapse of a predetermined period, withoutmaking any judgment of whether or not the exchange is necessary.

And, according to exposure apparatus 100, exposure of wafer W mountedwithin the inner periphery edge (within the depressed section on theupper surface of wafer table WTB) of opening 50 a of liquid-repellentplate 50 above wafer table WTB as is described above is performed (step254), by irradiating illumination light IL on wafer W. Accordingly,leakage of liquid (water) Lq from the space between wafer W andliquid-repellent plate 50 can be suppressed during exposure, and by theimmersion exposure, since exposure is performed with high resolution anda greater depth of focus compared with when exposure is performed in theair, the pattern of reticle R can be transferred with good precision onthe wafer, and for example, with an ArF excimer laser beam, a finepattern that has a device rule of around 45 to 100 nm can betransferred.

According to exposure apparatus 100 of the embodiment, since onlyminimum component members required for exposing the wafer, such as thewafer holder, need to be arranged on wafer stage WST (wafer table WTB),the size and weight of wafer stage WST can be reduced, which makes itpossible to reduce the size of the drive mechanism (motors) that drivethe wafer stage as well as reduce the heat generated from the motors,which in turn can suppress the thermal deformation of wafer stage WSTand degradation of exposure to the utmost.

In the embodiment above, the case has been described where a pluralityof measurement points is set on the outer periphery edge ofliquid-repellent plate 50 and the position information is obtained forthe measurement points. The present invention, however, is not limitedto this, and for example, at a position on the inner side of the outerperiphery edge position on the upper surface of liquid-repellent plate50, a mark whose position relation with the outer periphery edge isknown, such as a line-shaped mark parallel to the outer periphery edgeat a position a predetermined distance (referred to as D) away from theouter periphery edge, can be formed. And, at least one measurement pointcan be set on the mark and the position information measured, and theposition of the outer periphery edge can be obtained based on themeasurement results and distance D described above. As is shown in FIG.18, on liquid-repellent plate 50 in the vicinity of the edge, there aremany cases where there is a curved surface (or an oblique surface) of awidth d and height h, and because height h is approximately 0.1 mm, theimage of the edge may be blurred in the case the depth of focus ofalignment system ALG is shallow. In such a case, the line-shaped markreferred to above can be set at a position where D is greater than d(D>d), and the line-shaped mark can be imaged by alignment system ALG.As a matter of course, the mark is not limited to the line-shaped markdescribed above, and the mark may be of any shape, as long as theposition relation with the outer edge periphery is known.

Similarly, for the inner periphery edge of opening 50 a ofliquid-repellent plate 50, a mark whose position relation with the innerperiphery edge can be formed in advance, and the position information ofat least one measurement point on the mark may be obtained. For example,a line of a circle concentric with opening 50 a may be formed apredetermined distance outside the inner periphery edge of opening 50 a.

In addition, on detecting the position information such as the outerperiphery edge of liquid-repellent plate 50, it is desirable to use afocal point detection system that alignment system ALG has. In the case,however, when the detection beam of the focal point detection system ofalignment system ALG moves away from liquid-repellent plate 50, it isdesirable to perform the so-called shift focus operation where theposition of the measurement points is set within the imaging field ofalignment system ALG after focus alignment is performed once at aposition where the detection beam can be irradiated on the surface ofliquid-repellent plate 50.

In addition, in the embodiment above, the case has been described wherethe position information of each measurement point is obtained by theimage processing method using the imaging results of the image of theouter periphery of liquid-repellent plate 50, the inner periphery edgeof opening 50 a, or the outer periphery edge of tool wafer W1 or wafer Wpicked up using alignment system ALG consisting of a sensor by the FIAsystem. However, as the detection unit, sensors other than the FIAsystem, such as a unit that detects reflection light or scattered lightmay also be used. Further, in the case of using the FIA system, themethod of detecting the reflected light from the object by downwardillumination may naturally be used, however, it is also possible toilluminate the edge of liquid-repellent plate 50 from below and detectthe transmitted light above liquid-repellent plate 50.

In the embodiment descried above, at least one of the exchange operationof liquid-repellent plate 50 and the various measurements ofliquid-repellent plate 50 may be performed in a state without liquid Lqon the image plane side of projection optical system PL, or theoperation may be performed in a state with liquid Lq held in the spacebetween measurement table MTB and projection optical system PL. In thecase of keeping liquid Lq held in the space between measurement tableMTB and projection optical system PL, because the tip surface ofprojection optical system PL can be maintained in a wet state, not onlycan water marks or the like be kept from being generated but also theoperation of total recovery and re-supply of liquid Lq can be omitted.

In addition, in the embodiment described above, the case has beendescribed where wafer table WTB constitutes the first stage (and amoving body) on which the plate whose position information of the outerperiphery edge is detected is detachably mounted, and measurement stageMST constitutes the second stage. However, the present invention is notlimited to this, and measurement table MTB may constitute the firststage (and the moving body). That is, the position information of theouter periphery edge of a plate detachably mounted on measurement tableMTB may be obtained. In this case, the movement of measurement table MTBcan be controlled, based on the position information of the outerperiphery edge. In this case, at least one of the plate exchangeoperation of measurement table MTB and the various measurements of theplate may be performed in a state without liquid Lq on the image planeside of projection optical system PL, or the operation may be performedin a state with liquid Lq held in the space between wafer table WTB andprojection optical system PL.

The exchange operation of liquid-repellent plate 50 of wafer table WTBor the measurement operation of the outer periphery edge ofliquid-repellent plate 50 and the inner periphery edge of opening 50 aof liquid-repellent plate 50 may be performed in a state where liquid Lqis held in the space between measurement table MTB and projectionoptical system PL.

More specifically, when liquid-repellent plate 50 is exchanged on theside of wafer table WTB, the position of measurement table MTB iscontrolled so that liquid Lq is positioned above measurement table MTB,as is shown in FIG. 19A. Then after the exchange of liquid-repellentplate 50 has bee completed, the outer periphery edge of liquid-repellentplate 50 on the side (the +Y side) of measurement table MTB (measurementstage MST) is measured, using alignment system ALG, as is shown in FIG.19B. With this operation, it becomes possible to move wafer table WTB(wafer stage WST) closer to measurement table MTB (measurement stageMST).

Next, the outer periphery edge of liquid-repellent plate 50 on the −Xside and the outer periphery edge of liquid-repellent plate 50 on the +Xside are sequentially measured using alignment system ALG, as is shownin FIGS. 19C and 19D.

Then, based on the position information of the three points on the outerperiphery edge of liquid-repellent plate 50 obtained in the mannerdescribed above or the position information of liquid-repellent plate 50obtained from the position information above, main controller 20subsequently performs position control of wafer table WTB (wafer stageWST).

After the position information of the outer periphery edge ofliquid-repellent plate 50 is measured as is described above, forexample, wafer stage WST and measurement stage MST are integrally movedwhile maintaining a state where (liquid-repellent plate 50 of) wafertable WTB and measurement table MTB come into contact with (or are closeto) each other, and the inner periphery edge of opening 50 a ofliquid-repellent plate 50 on the +Y side is measured using alignmentsystem ALG, as is shown in FIG. 20A. Next, both stages WST and MST aresequentially moved integrally, while maintaining the state where(liquid-repellent plate 50 of) wafer table WTB and measurement table MTBcome into contact with (or are close to) each other, and the innerperiphery edge of opening 50 a of liquid-repellent plate 50 on the −Xside and the inner periphery edge on the +X side are sequentiallymeasured using alignment system ALG, as is shown in FIGS. 20B and 20C.In this case, since there is no wafer mounted on wafer table WTB, liquidLq cannot be positioned at the point where the wafer is mounted,however, because the inner periphery edge can be measured as is shown inFIGS. 20A to 20C, it is possible to load wafer on wafer holder WH in amanner similar to the embodiment above based on the measurement results.

As is described above, by performing the exchange operation ofliquid-repellent plate 50 of wafer table WTB and the measurementoperation of the outer periphery edge of liquid-repellent plate 50 orthe inner periphery edge of opening 50 a of liquid-repellent plate 50 ina state with liquid Lq held in the space between measurement table MTBand projection optical system PL, the recovery operation and the supplyoperation of the liquid will not be necessary, which means that the timerequired for the operations can be cut, which in turn makes it possibleto increase the throughput in the exposure process.

As is described above, after the outer periphery edge ofliquid-repellent plate 50 and the inner periphery edge of opening 50 aare measured and the wafer is loaded on wafer holder WH, the movementrange in a state where liquid-repellent plate 50 of wafer stage WST(wafer table WTB) on which the wafer is loaded and measurement table MTBcome into contact with each other broadens. That is, it becomes possibleto position liquid Lq on the entire surface of wafer table WTB.Accordingly, measurement using the measurement method according to theflowcharts in FIGS. 7, 11, and 12 described in the above embodiment maybe performed again. Such an arrangement makes it possible to performmeasurement with high precision.

In addition, in the embodiment above, the case has been described wherethe measurement points for position information are set at a pluralityof areas symmetry to the center for each of the outer periphery ofliquid-repellent plate 50, the inner periphery of opening 50 a, and theouter periphery edge of tool wafer W1 or wafer W. Such an arrangementwas employed, however, merely because an improvement in the measurementaccuracy could be expected by the averaging effect when calculating theposition of each center point, and it is a matter of course that thepresent invention is not limited to this.

In addition, in the embodiment above, the case has been described wherethe shape of liquid-repellent plate 50 is substantially a square andopening 50 a is a circle. The shape of the plate, however, may be acircle, a polygon, or any other shape, and the opening also may be ofany shape as long as the shape corresponds to the object subject toprocessing. For example, in the case a liquid crystal display device isthe object subject to processing, the shape of the opening can be asquare according to the shape of the glass plate, serving as the objectsubject to processing.

In addition, in the embodiment above, the case has been described whereplate 50 is detachable to wafer table WTB, however, plate 50 may beformed integral with wafer table WTB. In this case as well, the positioninformation of the inner periphery edge of the depressed section formedin order to mount wafer W on wafer table WTB can be detected, as isshown in FIGS. 11 and 13.

In addition, in the embodiment above, the series of operations includingmeasuring the position information of the outer periphery edge of theplate described using FIG. 7 and the series of operations includingmeasuring the position information of the inner periphery edge of theopening of the plate described using FIG. 11 do not necessarily have tobe performed together, and performing only one of the series ofoperations is acceptable.

In the embodiment above, the case has been described where the presentinvention is applied to a liquid immersion exposure apparatus, however,the scope of the present invention is not limited to this, and thepresent invention can be suitably applied to a typical scanning stepperwhich is not of the immersion type. In this case, instead of theliquid-repellent plate, a plate that does not have a liquid-repellentsurface formed can be used.

In addition, in the embodiment above, the case has been described wherethe stage unit is equipped with a wafer stage and a measurement stage.However, the present invention is not limited to this, and the stageunit may be equipped with at least one wafer stage for holding thewafer, without being equipped with the measurement stage. In the casethe stage unit is equipped with a plurality of wafer stages, at leastone of the plate exchange operation and the various measurementoperations on one of the stages may be performed in a state withoutliquid Lq on the image plane side of projection optical system PL, orthe operation may be performed in a state where the other stage isarranged below projection optical system PL (on the image plane side)and liquid Lq is held in the space between the projection optical systemand the other wafer stage.

In addition, in the embodiment above, the case has been described wherethe arrangement of leveling table 52 having six degrees of freedom andmeasurement table MTB having three degrees of freedom are employed. Thepresent invention, however, is not limited to this, and the arrangementof leveling table 52 having three degrees of freedom and measurementtable MTB having three degrees of freedom may also be employed. Further,the arrangement of measurement table MTB having six degrees of freedom,without arranging leveling table 52, may also be employed.

In the embodiment above, pure water (water) is used as the liquid,however, as a matter of course, the present invention is not limited tothis. As the liquid, a liquid that is chemically stable, having hightransmittance to illumination light IL and safe to use, such as afluorine containing inert liquid may be used. As such as afluorine-containing inert liquid, for example, Fluorinert (the brandname of 3M United States) can be used. The fluorine-containing inertliquid is also excellent from the point of cooling effect. In addition,as the liquid, a liquid which has high transmittance to illuminationlight IL and a refractive index as high as possible, and furthermore, aliquid which is stable against the projection optical system and thephotoresist coated on the surface of the wafer (for example, cederwoodoil or the like) can also be used. Further, in the case the F₂ laser isused as the light source, fombrin oil may be chosen.

In addition, in the embodiment above, the liquid that has been recoveredmay be reused. In this case, it is desirable to arrange a filter forremoving impurities from the liquid that has been recovered in theliquid recovery unit, in the recovery pipes, or the like.

In the embodiment above, the optical element of projection opticalsystem PL closest to the image plane side is tip lens 91. The opticalelement, however, is not limited to lenses, and it may be an opticalplate (parallel plane plate) used for adjusting the optical propertiesof projection optical system PL such as aberration (such as sphericalaberration, coma, or the like), it may simply be a cover glass. Thesurface of the optical element of projection optical system PL closestto the image plane side (tip lens 91 in the embodiment above) may besmudged by coming into contact with the liquid (water, in the embodimentabove) due to scattered particles generated from the resist by theirradiation of illumination light IL or adherence of impurities in theliquid. Therefore, the optical element is to be fixed freely detachable(exchangeable) in the lowest section of barrel 40, and may be exchangedperiodically.

In such a case, when the optical element that comes into contact withthe liquid is a lens, the cost for replacement parts is high, and thetime required for exchange becomes long, which leads to an increase inthe maintenance cost (running cost) as well as a decrease in throughput.Therefore, the optical element that comes into contact with the liquidmay be, for example, a parallel plane plate, which is less costly thanlens 91.

In addition, in the embodiment above, the case has been described wherethe present invention is applied to a scanning exposure apparatus by thestep-and-scan method or the like. It is a matter of course, that thepresent invention is not limited to this, and more specifically, thepresent invention can also be applied to a projection exposure apparatusby the step-and-repeat method, an exposure apparatus by thestep-and-stitch method, an exposure apparatus by the proximity method,and the like.

As the usage of the exposure apparatus, it is not limited to exposureapparatus for manufacturing semiconductor devices, and for example, thepresent invention can be widely applied to an exposure apparatus formanufacturing liquid crystal displays which transfers a liquid crystaldisplay deice pattern onto a square shaped glass plate, and to anexposure apparatus for manufacturing organic EL, thin-film magneticheads, imaging devices (such as CCDs), micromachines, DNA chips, and thelike. In addition, the present invention can also be suitably applied toan exposure apparatus that transfers a circuit pattern onto a glasssubstrate or a silicon wafer not only when producing microdevices suchas semiconductors, but also when producing a reticle or a mask used inexposure apparatus such as an optical exposure apparatus, an EUVexposure apparatus, an X-ray exposure apparatus, or an electron beamexposure apparatus.

The light source of the exposure apparatus in the embodiment above isnot limited to the ArF excimer laser, and a pulsed laser light sourcesuch as a KrF excimer laser (output wavelength 248 nm), an F₂ laser(output wavelength 157 nm), an Ar₂ laser (output wavelength 126 nm), andKr₂ laser (output wavelength 146 nm), or the like, or an ultrahigh-pressure mercury lamp that generates a bright line such as theg-line (wavelength 436 nm) or the i-line (wavelength 365 nm) can also beused. In addition, a harmonic generating unit or the like of a YAG lasercan also be used. In addition, a harmonic wave may also be used that isobtained by amplifying a single-wavelength laser beam in the infrared orvisible range emitted by a DFB semiconductor laser or fiber laser, witha fiber amplifier doped with, for example, erbium (or both erbium andytteribium), and by converting the wavelength into ultraviolet lightusing a nonlinear optical crystal. Further, the projection opticalsystem is not limited to a reduction system, and the system may beeither an equal magnifying system or a magnifying system.

In addition, in the embodiment above, the case has been described of anexposure apparatus that uses a mask (reticle) of the light transmittingtype, which is a substrate of the light transmitting type where apredetermined light-shielding pattern (or a phase pattern or anextinction pattern) is formed. However, the present invention can alsobe applied to an exposure apparatus that uses an electronic mask (avariable shaped mask) which forms a transmittance pattern, a reflectionpattern, or an emission pattern, based on the electronic data of thepattern that is to be exposed as is disclosed in, for example, U.S. Pat.No. 6,778,257, instead of the reticle above.

In addition, as is disclosed in the pamphlet of InternationalPublication No. WO 01/035168, by forming interference fringes on waferW, the present invention can also be applied to an exposure apparatus (alithography system) that forms line-and-space patterns on wafer W.

In the embodiment above, the case has been described where the positionmeasurement method, the measurement method, and the loading method ofthe present invention are applied to an exposure apparatus. However, thepresent invention is not limited to this, and the position measurementmethod of the present invention can be applied to a unit as long as theunit is equipped with a moving body on which a plate of a predeterminedshape is detachably mounted, and the measurement method and the loadingmethod of the present invention can be applied to a unit as long as theunit is equipped with a moving body on which a plate that has an openingformed for placing an object is detachably mounted.

Semiconductor devices are manufactured through the following steps: astep where the function/performance design of a device is performed; astep where a reticle based on the design step is manufactured; a stepwhere a wafer is manufactured using materials such as silicon; alithography step where the pattern formed on the mask is transferredonto a photosensitive object by the exposure apparatus described in theembodiment above; a device assembly step (including processes such asdicing process, bonding process, and packaging process); inspectionstep, and the like. In this case, in the lithography step, because theexposure apparatus and the exposure method in the embodiment above areused, exposure with high precision can be achieved for over a longperiod of time. Accordingly, the productivity of high-integrationmicrodevices on which fine patterns are formed can be improved.

While the above-described embodiment of the present invention is thepresently preferred embodiment thereof, those skilled in the art oflithography systems will readily recognize that numerous additions,modifications, and substitutions may be made to the above-describedembodiment without departing from the spirit and scope thereof. It isintended that all such modifications, additions, and substitutions fallwithin the scope of the present invention, which is best defined by theclaims appended below.

What is claimed is:
 1. An exposure apparatus that exposes a substrate with an exposure beam via a projection optical system and a liquid, the apparatus comprising: a holding member that holds the projection optical system; a detection device provided at the holding member, away from the projection optical system; a local liquid immersion system that has a nozzle member provided in proximity to a lens, and forms a liquid immersion area under the projection optical system with a liquid supplied via the nozzle member and also recovers the liquid of the liquid immersion area via the nozzle member, the lens being placed on a most-image-plane side of a plurality of optical elements of the projection optical system; a base placed below the projection optical system and the detection device; a stage that is placed on the base and holds the substrate in a depressed section of an upper surface of the stage, the upper surface being capable of coming into contact with the liquid immersion area; a drive system that has a motor and moves the stage, a part of the motor being provided at the stage; a carrier system that has a pre-alignment device of the substrate and carries a substrate to which pre-alignment has been performed by the pre-alignment device to above the stage placed at an exchange position of the substrate, the exchange position being away from the projection optical system; and a controller that controls at least one of the stage and the carrier system based on positional information of the depressed section obtained by the detection device, in order to load the substrate on the stage so that the substrate carried to above the stage by the carrier system is mounted in the depressed section, wherein the substrate is mounted in the depressed section so that a gap is formed between a surface of the substrate and the upper surface of the stage, and the stage is moved, so that the substrate mounted in the depressed section moves relative to the liquid immersion area formed between the projection optical system and a part of the substrate and also the liquid immersion area traverses the gap.
 2. The exposure apparatus according to claim 1, wherein at least a part of the liquid immersion area that moves off from the substrate mounted in the depressed section is maintained under the projection optical system by the upper surface of the stage.
 3. The exposure apparatus according to claim 2, wherein the substrate is mounted in the depressed section so that the surface of the substrate is flush with the upper surface of the stage.
 4. The exposure apparatus according to claim 3, wherein the upper surface of the stage is liquid-repellent.
 5. The exposure apparatus according to claim 3, wherein a positional relationship between the substrate and the stage is set so that the substrate does not come into contact with the upper surface of the stage in the loading and the gap is smaller than a predetermined value.
 6. The exposure apparatus according to claim 5, wherein the substrate is mounted in the depressed section so that the gap is not more than about 0.3 mm or the gap is substantially even.
 7. The exposure apparatus according to claim 3, further comprising: a position measurement system that measures positional information of the stage, wherein while the positional information of the stage is measured by the position measurement system, a part of the stage is detected by the detection device, in order to obtain positional information of the depressed section.
 8. The exposure apparatus according to claim 7, wherein the positional information of the depressed section is obtained at a plurality of parts of the depressed section, and information on a center position or a shape of the depressed section is obtained.
 9. The exposure apparatus according to claim 7, further comprising: another stage different from the stage, wherein during a loading operation of the substrate onto the stage, the liquid immersion area is maintained under the projection optical system by the another stage.
 10. The exposure apparatus according to claim 9, wherein the another stage has a measurement member on an upper surface of the another stage, the measurement member being irradiated with the exposure beam via the projection optical system and the liquid of the liquid immersion area, and measurement using the measurement member is performed while the liquid immersion area is maintained under the projection optical system by the another stage.
 11. A device manufacturing method, including: a lithography process that uses the exposure apparatus according to claim 1; and a device assembly process.
 12. An exposure method of exposing a substrate with an exposure beam via a projection optical system and a liquid, the method comprising: placing a stage on an exchange position of the substrate, the stage being placed on a base placed below the projection optical system and a detection device and holding the substrate in a depressed section of an upper surface of the stage, the projection optical system and the detection device being provided away from each other at a holding member, and the upper surface being capable of coming into contact with a liquid immersion area formed under the projection optical system; carrying a substrate to which pre-alignment has been performed, to above the stage placed at the exchange position, with a carrier system having a pre-alignment device of the substrate; and controlling at least one of the stage and the carrier system based on positional information of the depressed section obtained by the detection device, in order to load the substrate on the stage so that the substrate carried to above the stage is mounted in the depressed section, wherein the liquid immersion area is formed under the projection optical system with a liquid supplied via a nozzle member and also the liquid of the liquid immersion area is recovered via the nozzle member, the nozzle member being provided in proximity to a lens that is placed on a most-image-plane side of a plurality of optical elements of the projection optical system, the substrate is mounted in the depressed section so that a gap is formed between a surface of the substrate and the upper surface of the stage, and the stage is moved, so that the substrate mounted in the depressed section moves relative to the liquid immersion area formed between the projection optical system and a part of the substrate and also the liquid immersion area traverses the gap.
 13. The exposure method according to claim 12, wherein at least a part of the liquid immersion area that moves off from the substrate mounted in the depressed section is maintained under the projection optical system by the upper surface of the stage.
 14. The exposure method according to claim 13, wherein the substrate is mounted in the depressed section so that the surface of the substrate is flush with the upper surface of the stage.
 15. The exposure method according to claim 14, wherein the upper surface of the stage is liquid-repellent.
 16. The exposure method according to claim 14, wherein a positional relationship between the substrate and the stage is set so that the substrate does not come into contact with the upper surface of the stage in the loading and the gap is smaller than a predetermined value.
 17. The exposure method according to claim 16, wherein the substrate is mounted in the depressed section so that the gap is not more than about 0.3 mm or the gap is substantially even.
 18. The exposure method according to claim 14, wherein while positional information of the stage is measured with a position measurement system, a part of the stage is detected by the detection device, in order to obtain positional information of the depressed section.
 19. The exposure method according to claim 18, wherein the positional information of the depressed section is obtained at a plurality of parts of the depressed section, and information on a center position or a shape of the depressed section is obtained.
 20. The exposure method according to claim 18, wherein during a loading operation of the substrate onto the stage, the liquid immersion area is maintained under the projection optical system by another stage that is different from the stage.
 21. The exposure method according to claim 20, wherein the another stage has a measurement member on an upper surface of the another stage, the measurement member being irradiated with the exposure beam via the projection optical system and the liquid of the liquid immersion area, and measurement using the measurement member is performed while the liquid immersion area is maintained under the projection optical system by the another stage.
 22. A device manufacturing method, including: a lithography process that uses the exposure method according to claim 12; and a device assembly process. 